I just purchased a 2004 Mazda RX-8 with 26k miles, and even with keeping the RPMs down Im only getting 200 miles out of the 16 gallon fuel tank. The Mazda dealership is at a lost (And doesn't seem to care in the least), and I'm not sure what to do. Has anyone had this problem or have any suggestions?

No, you are the only person on this board getting bad gas mileage.

Okay, That previous post was just cruel.

There are many folks that have had gas mileage issues. Search the board for some appropriate answers and ideas.

Also, to achieve best fuel mileage, shift at the manufacturers recommendations for shift points (read the manual). Loosely translates to shifting at 3000rpm. Also great if you like shifting, as you'll shift 4 times to get to 40mph.

No, you are the only person on this board getting bad gas mileage.

That's just mean dood! =)

wow...thats deep...there are several of us that get this kind of mileage....at best i have gotten 240ish out of a tank with mixed driving.....if you search out this forum there are plenty of threads that deal with this....you are not alone and mazda will do nothing about it....it is after all a sports car so just enjoy it and drive it like you stole it.....do you know if your flashes are current and if the car has had its maintenance done?....that could help some....there are some abnormal cars out there that have also brok 300 to the tank but they are pretty rare....

where are you located. at or mt? what fuel do you use

it is NOT abnormal to get more than 300 per tank- thats just highway driving

16-17 here..

~20 mph here.

~20 mph here.

So do you drive EVERYWHERE at that speed??? :mdrmed:


I'm getting 20-21mpg out of my 06'. I even squeezed 314 miles out of a tank once. I feel for your 12 though....that sucks. Almost sounds as bad as driving my Jeep that has a 360 V-8........ it ranges anywhere from 7 to 8 mpg.

Love the car! Would just prefer the 18-24 MPG that they advertise. Thanks for the help though.

I float between 220 and 240(250 once) per tank(14-15+ gallons)...

it would be nice to have a 300 mile range

It's a MT in eastern PA north of Philly. I've been trying to shift around 3k RPMs.

I just purchased a 2004 Mazda RX-8 with 26k miles, and even with keeping the RPMs down Im only getting 200 miles out of the 16 gallon fuel tank. The Mazda dealership is at a lost (And doesn't seem to care in the least), and I'm not sure what to do. Has anyone had this problem or have any suggestions?
How much gas did you fill up when you got 200 miles on your tank?

If you do the math, at 200 miles, you are putting in approximately 16.67 gallons in your tank. By my estimation, that is practically bone dry.

More realistically, if you put about 14 gallons in your fillup, at 200 miles you are getting 14.3 mpg. Still sucks, but sounds a little more realistic.

I am almost always north of 17mpg, closer to 18mpg most times. Only a couple of times have I dropped below 17. I'm guessing that is closer to the "norm". On a "full" tank, that is about a 220-230 mile range, and a 13-14 gallon fillup.

I filled it up with 15 gallons last time. I purposely let it get really low to see my MPG more accurately. Every 50 miles it goes down a quarter of a tank. Maybe I'm getting 13, but no more than that. It has been serviced recently, and doesn't need a tune-up yet. I put 93 Octane in it, and the air filter and housing is clean. The tire pressure is good, and I haven't been using my A/C either.

get it out on the highway and FLOOR it. Keep it in 3rd if you have too and run it over 7K for a while.

change gas stations. use quality gas.. the cheap shit is just that. 87 gets me better milage. good 87 is better than cheap 93.

I'm a good 50/50 of city highway and I always get about 22 mpg, more on the highway, but you really have to run the car and keep it happy.

if you still have crummy gas mileage one more thing to try.. after driving. park, go into nuetral and rev then engine, hold it steady at 5k or so until the car gets hot, you want the temp gauge to start moving, or to hit the too hot fuel cut. make sure your thermostat is working. if it's sticking it can kill your milage.

Welcome to the club!

I filled it up with 15 gallons last time. I purposely let it get really low to see my MPG more accurately. Every 50 miles it goes down a quarter of a tank. Maybe I'm getting 13, but no more than that. It has been serviced recently, and doesn't need a tune-up yet. I put 93 Octane in it, and the air filter and housing is clean. The tire pressure is good, and I haven't been using my A/C either.

First thing you need to do is use 3rd grade math to properly determine your MPG.

Reset your trip every fill up, then take the miles you've made and divide it by the number of gallons you put into your car when you filled up.

By doing this A) you get the proper MPG (which will be higher then 12), B) you dont have to drain the tank completely to find out your MPG, C) You stop making threads about 12mpg when you're really getting better then that.

Example, 250 miles on my trip, i put in 13.5 gallons when i filled up...

250 divided by 13.5 = 18.52mpg

First of all, I said I put 15 gallons in it. I only got 200 miles from it. I am on extreme E and have used between 15 and the max of 15.9 gallons of fuel. Hence around 13 MPG which I previously stated the correction from 12. Thanks for your input though.

First of all, I said I put 15 gallons in it. I only got 200 miles from it. I am on extreme E and have used between 15 and the max of 15.9 gallons of fuel. Hence around 13 MPG which I previously stated the correction from 12. Thanks for your input though.

use my simple 3rd grade forumla on your next fillup, let us know what it says.

And all that is with me purposely driving like a granny. Can't imagine if I almost redlined it alot, lol! Probably get like 10 or 11. Oh well, I still love her.

use my simple 3rd grade forumla on your next fillup, let us know what it says.

I know very few third graders who are driving enough to calculate their gas mileage.

And all that is with me purposely driving like a granny. Can't imagine if I almost redlined it alot, lol! Probably get like 10 or 11. Oh well, I still love her.

this car NEEDS to be redlined... frequently. driving it like a ganny WILL kill it.

get it out on the highway and FLOOR it. Keep it in 3rd if you have too and run it over 7K for a while.

change gas stations. use quality gas.. the cheap shit is just that. 87 gets me better milage. good 87 is better than cheap 93.

I'm a good 50/50 of city highway and I always get about 22 mpg, more on the highway, but you really have to run the car and keep it happy.

if you still have crummy gas mileage one more thing to try.. after driving. park, go into nuetral and rev then engine, hold it steady at 5k or so until the car gets hot, you want the temp gauge to start moving, or to hit the too hot fuel cut. make sure your thermostat is working. if it's sticking it can kill your milage.


So what is good gas? Mobile, sunoco, hess?????????

So what is good gas? Mobile, sunoco, hess?????????
I remember there's a topic somewhere here that has a list of "certified" stations. Included were Shell, 76, and a bunch of others. The suppliers of those gassolines supposidly meet a certain set of standards. Anyways, just search for that topic.

wow... didn't realize these 3 pages were all from 3 hours

I just filled it up again. I'm quite aware of your little 3rd grade equation. I went 197 miles and used up 15.2 gallons using an average of 12.96 MPG. I was previously stating a guesstimation of the MPG and gee...I was quite close wasn't I, CLEOENT. To the rest of you I very much appreciate your advice and I will try high revving it. Anyone think I should use a fuel injector cleaner on it? Not sure if that's alright with a rotary.

You must be doing city driving and alot of warm up time and short trips.

It should be more like 16.7 MPG

I can get 22.5 MPG on all Hwy. All city driving and short trips kills your MPG.

Try going up a steep hill. If your car bogs and can not accelerate normaly the you have a clogged CAT. That will kill MPG. CAT is covered under warrenty.

I'm pretty new to this club and I am already sick of all the "Mileage" threads. I know I can just stop opening these links but I'm afraid I'm addicted to this board and I love hearing people whine about how life sucks.

If you can't afford gas why not buy a Honda or Toyota? I wonder if other sports car clubs and off-road truck clubs complain about mileage....

I'm not complaining about the car. It calls for 18 MPG city driving, 24 for hwy driving. I'm getting 13 so therefore there is something mechanically or electronically wrong with my car. I seek to correct that problem. That is all. I'm fine with it running the way it was designed to run.

How many short trips do you take per tank?

Stop complaining, 12 - 16 mpg is normal for some 8's.
When you get 9 mpg like some of us you'll earn that right!
Besides, my knowledgeable service dept told me that 9 mpg is normal.
My bad mileage is due to grannying it, No wait! It's due to racing my AT
with bad gas...
They wouldn't lie to me... would they..!?!

Seriously...
Mazda doesn't have a clue why some 8's get poor mileage and others get 20+

It's easier to blame the customer for something they're doing wrong...

I do live in a small city, but it's surrounded by highways so it's a pretty even share of driving conditions. And as for short trips, probably the average is 15 min. considering in a city everything is pretty close including my job. I do give it at least 5 minutes before shutting it off as recommended.

Lol! Too true Eyeball! I think I have to agree with that. 9? Damn!

It calls for 18 MPG city driving, 24 for hwy driving. I'm getting 13 so therefore there is something mechanically or electronically wrong with my car.


not true- look at the sticker again. 18 is a median with 15 being possible driving like the test. your low may just indicate you are not driving like the test.

not saying you dont have an issue- just that your mpg doesnt automatically mean there is something wrong with the car

I do give it at least 5 minutes before shutting it off as recommended.


you let it sit at idle for 5 minutes every trip or close to it before shutting it off? does it sit that long running after start and before you start driving? theres your issue then

Lol! No, the manufacturer recommends to not run a rotary for less than 5 minutes at a time. And as I stated, I have tried driving it at lower RPMs to preserve the fuel. I have a degree in Automotive Technology, and I am a Service Adviser at a Mercedes, Audi, Porsche dealership. The mazda specialists are at a loss as well as me as to why I am getting such shitty MPG. It is below spec. I am just trying to see if maybe someone else had this problem as well and somehow corrected it. I don't believe the cat is bad because the o2 sensor is reading fine downstream. The air intake seems to be cleared and functioning properly. There is not any codes. The fuel trim is where it is suppose to be. Small things like the tire pressure are fine. I have tried to shift differently to see if that helped, but it didn't much. Air filter is fine, it is not due for a tune-up for another 10k miles and it recently had the routine service performed. I'm thinking maybe fuel injection cleaner, but I am not sure if that is safe for a rotary.

Tis normal. You're lucky to be gettin 200. i'm more like 185.

What you are experiencing, sir, is not a problem but a feature.

I read a thread in the last week or so where the guy (or girl) replaced their cat with a highflow one and got better gas mileage and better performance as a result. Before the swap they were getting some crappy mileage and the cup holder would boil water. I do not remember the particulars but I believe that they stated the O2 sensor was giving off normal readings before the swap. After the swap the cup holder was cool again and they got better mileage. Do a search to get the actual statements before you quote me on anything.

Tis normal. You're lucky to be gettin 200. i'm more like 185.

What you are experiencing, sir, is not a problem but a feature.

it's not normal... i've had two rx8's and both got around the same mileage. about 240 per tank in the city and about 280 on the highway.

his mileage sucks and should not be accepted because a few others are experiencing the problem.

I have a degree in Automotive Technology, and I am a Service Adviser at a Mercedes, Audi, Porsche dealership. The mazda specialists are at a loss as well as me as to why I am getting such shitty MPG. It is below spec. I am just trying to see if maybe someone else had this problem as well and somehow corrected it. I don't believe the cat is bad because the o2 sensor is reading fine downstream.


well the degree could be your problem :D: i keed i keed

ok- do not believe that the cat is ok because the O2 sensor is reading fine and there isnt a code. i could link you to a whole slew of posts that had bad cats and no cel. it will eventually but only when the honeycomb breaks lose. and even then it might not. just recently had another one. a freind had an issue and after driving the car i and others said bad cat. of course his dealer said no CEL etc. he went to another dealer that dropped the cat and pieces fell out. pull the cat and physically look at it from both ends.

also pull your coils and look at the back. if there is evidence of melting or burning or the plate they sit on looks like there was arcing going on change the coils. pull the plugs and see if they are fouled. also check that you have the new style plugs and not the old style.

it's not normal... i've had two rx8's and both got around the same mileage. about 240 per tank in the city and about 280 on the highway.

his mileage sucks and should not be accepted because a few others are experiencing the problem.
A few?

what would you consider to be normal for all city driving?

On what would you be basing your assessment?

it's not normal... i've had two rx8's and both got around the same mileage. about 240 per tank in the city and about 280 on the highway.

his mileage sucks and should not be accepted because a few others are experiencing the problem.

Well, from what I experience, the longevity of each fuel tank is greatly effected by the amount of short trips. I drive to school, to/from lunch, and home form school every day. That is a ton of short trips and if I do not drive any highway in that time, and use up the whole tank, I get about 200mi or so. If I drive with highway included, the number can get up to around 240. I never realized how much the different kinds of trips could effect mileage before this car...

thats exactly it- that extra trip around the block for lunch(really 2 starts adn 2 short trips) will kill the mileage especiall if they are not accompanied by a nice easy cruise on the freeway home(no stop and go just light throttle highest gear possible etc)

thats exactly it- that extra trip around the block for lunch(really 2 starts adn 2 short trips) will kill the mileage especiall if they are not accompanied by a nice easy cruise on the freeway home(no stop and go just light throttle highest gear possible etc)

Heh, I'm not the one complaining though :)

I've read somewhere that car companies test their cars' mpg basically on a treadmill so there's little air resistance and friction... in other words the most ideal conditions. So I would expect the mpg less than the advertised number.

I also got 12-13mpg all the time I shifted at 6500rpms to 7500rpms

Thanks for the advice. I think I'll look into the cat issue first. And the plugs as well.

As some have mentioned the gas you put in can make a big difference. I just got back from a trip and got 22.9 mpg on 87 octane and got over 25 mpg on shell v power 93 octane more than once with almost the exact same driving conditions. My car obviously likes that specific kind of gas.

200 miles on a tank? Same here.

However, I also have a 2nd car that gets 25mpg city and 30mpg highway that I can drive if I ever tire of spending $45 a week on gas. :)

250ish per tank ,,mostly freeway at 4000 rpm

My best milage, and the best reported by a lot of people, is when I can do a long run at 70-80 mph - If you can't get anything else to work, save up your bucks and take her on a long run - if it isomething on the rotars, or if it is a clogged fuel system it may shake it loose - and use a blastedly expensive grade of gas, like shell -

But first, replace your battery - a flakey battery doesn't provide proper ignition, and make sure your belts are tight - with that low a milage, either gas is not getting where is should, or it's not igniting properly, or it is being lost some place, if you were a standard engine I would suggest you are not running on all pistons.... Are you getting a lot of heating? If its not anything else then check the transmission - because the power is not getting to the wheels -Are you running some sort of odd tires?

The only good news I can give you is that our Mobil Station Manager says he thinks California gas prices have peaked and should begin to drop, so other states may drop also. OPEC says they will remain constant on production so that will effect the spot market, and Sen Barbara Boxer is sniffing around like she did with ENRON - she feels that the highest gas prices in the Country charged in California are a personal insult to her intellegence - especially since we did not get hurricaned. The FTC is also snooping, and Mobil/Exxon just had a stock holders meeting and they demanded the newly retired CEO return half of his retirement package...

i barely reach 200 with DCM on, with it off. i get around 240 - 260 with full tank.
mine is AT/ 2005 Pearly.., since im in LA, I heard in CA- the chemicals they put in gas is the problem with bad gas milage. I usually put in octane booster when i fill up, i think it helps.

As some have mentioned the gas you put in can make a big difference. I just got back from a trip and got 22.9 mpg on 87 octane and got over 25 mpg on shell v power 93 octane more than once with almost the exact same driving conditions. My car obviously likes that specific kind of gas.

isn't 87 bad for the engine?

And all that is with me purposely driving like a granny. Can't imagine if I almost redlined it alot, lol! .

As a full time, professional, resident, little old lady, i.e. Granny (and driver of a great granny) - you need to know that we took Rotar God's advice, and we red line our engine at least once a week because it knocks oil deposites off the rotar and that helps milage. (See his string on synthetic oil) We found, by accident of course, that if you should be stopped at a red light, and a nice young man shows off the fun noises his engine can make, it is a very opportune time to red line your engine. Sometimes that demonic vacumn sweeper married to a jet engine sound will confuse the enemy! (Do not start the demonstration, especially if the nice young man happens to be a policeman)

:rock:

A few?

what would you consider to be normal for all city driving?

On what would you be basing your assessment?

i'm basing my assessment on the million threads posted here regarding mpg. it's one person stating their gas mileage sucks, then most of the others stating that they get 16-22 mpg and there must be something wrong.

i'm not saying that a driver cannot get 180 miles to a full tank if he tries. However, these posters are saying that they are driving normally (50/50 highway and street, shifting at reasonable rpms, etc) and still getting anywhere up to 10 mpg fewer than others. that's not normal, nor should it be accepted as such. i'm not suggesting that there aren't a lot of people with this problem, but 12 mpg is not normal.

isn't 87 bad for the engine?

A lot of people on the forum prefer it and feel their car runs better on it.

i'm basing my assessment on the million threads posted here regarding mpg. it's one person stating their gas mileage sucks, then most of the others stating that they get 16-22 mpg and there must be something wrong.

i'm not saying that a driver cannot get 180 miles to a full tank if he tries. However, these posters are saying that they are driving normally (50/50 highway and street, shifting at reasonable rpms, etc) and still getting anywhere up to 10 mpg fewer than others. that's not normal, nor should it be accepted as such. i'm not suggesting that there aren't a lot of people with this problem, but 12 mpg is not normal.
If our friend is getting 180ish per tank that works out to 14-15 mpg not 12. Although he or she emphasized 12 in the subject, the math doesn't add up.

If you and I are reading the same posts where members speak of their fuel economy sucking balls, 15 mpg - 17mpg city driving seems pretty normal to me.

Whether or not this is something we should accept, is something that doesn't require much discussion.

What we can actually do about, is something that I would like to get some input on.

Do you have any ideas?

I'm really excited because my city mileage for the 1st time just hit 13mpg. If this keeps improving I might beat my neighbors Hummer's mileage.

I get an average of 190 miles per full tank, and about 95 miles for a half tank. I think that's pretty good considering I keep the rpm's above 4000rpm's almost always.

If our friend is getting 180ish per tank that works out to 14-15 mpg not 12. Although he or she emphasized 12 in the subject, the math doesn't add up.

actually 180 per tank = 12mpg. Rx-8 has capacity of 15 gallon. 15*12=180. get it? got it! good.

15.9 gallons...so call it 16. :)

16 gallons would be when you run the tank completely dry. I'm pretty sure the light comes on at about 13 gallons because this past time I drove until the light came on (246.6mi) and it only filled up 13.6 gallons (about 18.1mpg mixed driving!) That means when people say to be getting about 200mi per tank, I'd assume they fill up when the light comes on (rather than running the car completely dry :p) thus meaning those people get ~15.4mpg... If the light comes on at 156mi, then you're getting 12mpg.

The worst I have ever gotten was 14-15 and that was a full tank in one day. I love love love long long long canyon runs :)

actually 180 per tank = 12mpg. Rx-8 has capacity of 15 gallon. 15*12=180. get it? got it! good.
Is it more likely that he's filling up around when the light comes on (13-ish gallons)? or is it more likely that he's filling up when the car is running on fumes (15-ish gallons)?

Is it more likely that he's filling up around when the light comes on (13-ish gallons)? or is it more likely that he's filling up when the car is running on fumes (15-ish gallons)?

he/she has already stated that he's filling up at over 15 gallons.

To all, some may complain about our fellow 8 Driver that is getting 12 mpg... I also feel his pain... I have also recently purchased a 2004 Mazda RX-8 (auto), 23K, and it sucks at fuel efficiency... averaging maybe 15 mpg... 50/50 driving... I have seen it as low as 12 mpg... I honestly thought my car was having some serious problems but after reading all of these postings... I see that I am not alone...

Reading all of the other write ups and comments I see that Mazda has made a car that gets nowhere near what they advertise.. Almost needs to be launched as a Class Action Law Suit for some lawyer that wants to see if he can make a few extra $$$$...

I will try and change my driving habits and see if it improves... thanks for all of your inputs...

It may be superstition, but I have heard that if you refill when your tank is half full, and refuel in the cooler part of the day, you get better milage - also the weight of the driver/passenger/luggage may have an effect - an old bike racing theory states that 1 pound of load is 5 pounds of push on the wheel, increasing to 7 going up hill. Thus, a little old lady of 120 lbs may get better milage than a big 200 plus male. I wonder what the weight of the passenger was set at in the milage tests?
Also, would you lighten the car sufficiently to improve milage if you ran the tank to E before refilling. Any of you engineering types know?

he/she has already stated that he's filling up at over 15 gallons. :banghead: :uh: thanks

To all, some may complain about our fellow 8 Driver that is getting 12 mpg... I also feel his pain... I have also recently purchased a 2004 Mazda RX-8 (auto), 23K, and it sucks at fuel efficiency... averaging maybe 15 mpg... 50/50 driving... I have seen it as low as 12 mpg... I honestly thought my car was having some serious problems but after reading all of these postings... I see that I am not alone...

Reading all of the other write ups and comments I see that Mazda has made a car that gets nowhere near what they advertise.. Almost needs to be launched as a Class Action Law Suit for some lawyer that wants to see if he can make a few extra $$$$...

I will try and change my driving habits and see if it improves... thanks for all of your inputs...
I'm with ya on this one.

LET'S SUE THE FUCKERS!!!!

I'm realized that keeping the RPMs down and driving it like a sports car really doesn't make much of a difference in fuel consumption so I've given up driving her like a granny. I first tried 93 Octane from Shell and since have tried Exxon and Mobil as well. All give me about the same MPG. As for the people asking about using a lower octane....Mazda calls for 91 or above because of it being a high compression engine. Using lower than 91 could cause pre-ignition, which damages a vehicle. Though I don't see it having as much damage on a rotary as much as it would to a 4-stroke engine. In other words, not going to be bending any valves. And for whoever might have missed it, I did correct myself in actually getting 13 MPG. 197 miles for 15.2 gallons. I brought it to fumes, lol! And still no conclusion to this problem. I am interested into looking at the possibility of their being a problem with the catalytic converter though. As for redlining it to clear it out....it's been done and nothing.

I'm realized that keeping the RPMs down and driving it like a sports car really doesn't make much of a difference in fuel consumption so I've given up driving her like a granny. I first tried 93 Octane from Shell and since have tried Exxon and Mobil as well. All give me about the same MPG. As for the people asking about using a lower octane....Mazda calls for 91 or above because of it being a high compression engine. Using lower than 91 could cause pre-ignition, which damages a vehicle. Though I don't see it having as much damage on a rotary as much as it would to a 4-stroke engine. In other words, not going to be bending any valves. And for whoever might have missed it, I did correct myself in actually getting 13 MPG. 197 miles for 15.2 gallons. I brought it to fumes, lol! And still no conclusion to this problem. I am interested into looking at the possibility of their being a problem with the catalytic converter though. As for redlining it to clear it out....it's been done and nothing.

Actually, pre-detonation is a lot worse for a rotary engine than a piston engine. Rotors can often by destroyed by just one bad knock.

Doesn't matter how I drive the car I still only get 210 to a tank. On long road trips I might get 250. (This would have to include hell freezing over)

I did the comparison driving 2 tanks the way I normally drive and 2 tanks the way that mazda recommends and I saved a total of 7 miles that tank. It was just not worth losing the thrill of beating the crap out of my engine for 2 tanks of gas.

This is just how this car is......there are only two things you can do:

1 - SELL IT and leave the forum

2- KEEP IT and tell us how you drive it like you stole it and love the crappy gas mileage that your rotary has bestowed upon you :smoker:

15.5-18.5 which is quite predictable looking at the size of your wheels

No point driving it like a granny, just keep it in 5000 rpm range. Its healthier that way for both you and the engine plus the mileage doesn't get affected much.

If enough people sue Mazda over this, there might be some new miracle flash... I'm getting 18mpg but i'm not satisfied.

I'm not really sure you can sue mazda over something like this... I'm pretty sure fuel mileage estimates are provided by the EPA, part of the government. They have nothing to do with mazda at all. However, the way the epa tests vehicles is absolutly hillarious. Highway milleage is calcated at about 48 mph while accelerating from 0-48 over the course of about 40 seconds. I'm sort of exagurating but car and driver had the figures in an article and they were gay as aids. I highly doubt anyone drives their rx8 like that.

No clue as to where Mazda feels they can state 18/25 for the RX-8. Legally, would not mess with it. My average MPG jumps all over the place from as low as 13 to as high as 19 MPG. But I have noticed that city driving (even a little of it) sucks the fuel out faster than I ever expected. The car does not like to sit at idle and it definitely does not like the repeated starts and shutdowns that come with city driving... I do find that the MPG goes up on the highway and my last tank was at 19 MPG. I have accepted the fact that 18/25 will never happen... I will take 13/19 and drive it like I want... But you have to admit... you look damn good driving down the road...

5/1/06 - Revi + Ram Air - 24,000 miles + installed new spark plugs with the Revi. – OEM tires, exhaust, 91 octane.

Mileage – 1st tank city, 21mpg + 1 over standard 18-20 – 2nd tank freeway cruise 23mpg + 2 over standard 20-22 - 3rd tank rush hour freeway and city, 21mpg. Overall, 1-2mpg better.

5mpg here

Update. I WAS getting 14mpg with what I would consider normal driving. So I started shifting at or just below 3000rpm, but still redlining it every so often when I want to have fun. My gas mileage has skyrocketed. Normally at 40 miles I'd already be down a 1/4 tank. Now I'm at 82miles on this tank and it just dropped below the 1/4 tank mark.

this car NEEDS to be redlined... frequently. driving it like a ganny WILL kill it.

So not pounding the car to death, redlining at every opportunity, is "killing" it?

I've got one word, or two letters, for that:

BS

When driving around town, shifting at 3000rpm or so is not "grannying" it, it's just taking it easy. You don't need to drive like a testosterone-addled teen EVERYWHERE you go, you know. "Driving it like you stole it" all the time is a great way to increase the wear and tear on the vehicle and lead to a premature demise, no matter what brand or model of car it is. Pound the car when appropriate, but drive it like any other car the rest of the time and you will get okay (not "good") mileage and decrease your maintenance costs, as well.

Update. I WAS getting 14mpg with what I would consider normal driving. So I started shifting at or just below 3000rpm, but still redlining it every so often when I want to have fun. My gas mileage has skyrocketed. Normally at 40 miles I'd already be down a 1/4 tank. Now I'm at 82miles on this tank and it just dropped below the 1/4 tank mark.


imagine that :)

I know. It's somthin' else. :)

I hit 22 mpg on the drive to Rochester. Of course, thats basically sitting in sixth on cruise for an entire tank. I don't imagine ever really getting better.

I just sit in my RX-8 and have a buddy tow me around.

:boring:

Today I had to fill my tank again. It's been 185 miles since filling last and had to put 14.2 gallons Mobil 93 Octane in it. 13 MPG. I have my dealership contacting the Mazda Technical support to look into possibilities, because they won't take a look at the cat without a code being set. Oh, and I don't beat my car, redlining all day everyday. When I said driving it like a granny, I was simply saying that I pretty much didn't take it over 4k for a whole tank, which only got me 20 extra miles. I drive it like a "granny" and a sports car and everywhere in between now. All of it equally divided between hwy and city driving. I will fill you all in on the conclusion if it ever happens, lol! I love this car though and so do the ladies, lol!

Lol! That's great!

I'm getting about 14 to 15mpg city driving. I get about 17mpg highway driving. I understand it's a sports car but good lord.

My driving is about 50/50 city/highway. I usually get about 240-250 per tank, and that is using about 13.5 gal., which comes out to about 18 mpg. I have gotten 300 on road trips. But 12 mpg is definitely really low.

I just purchased a 2004 Mazda RX-8 with 26k miles, and even with keeping the RPMs down Im only getting 200 miles out of the 16 gallon fuel tank. The Mazda dealership is at a lost (And doesn't seem to care in the least), and I'm not sure what to do. Has anyone had this problem or have any suggestions?

They aren't going to do anything because they can't do anything about it. It is simply one of the inconsistencies between the different rotary motors. Some get good mileage while some get horrible. When I had my 04 RX8 I would bitch about he fact I barely got 14mpg. I then slapped a turbo on, and it made city mpg much much worse. (Not that I was expecting anything better) Its just that I wanted a car that could go as fast as it can use up gas. Well, that didn't work either. I got fed up with it. I sold it bought a Lexus IS 350. I'm pushing 277 rwhp and getting an average of about 25 miles per gallon. And that's ragging on it. So for all of you who say that "you should have thought about that before getting a Sports Car" Then your wrong.
The 2006 SRT10 Viper gives 12- 20 mpg,
2006 Corvette ZO6 16 mpg in city traffic and 26 mpg.

I say get a different sports car or get a different RX8.. Although this car looks bad ass and big time eye candy (especially from the girls) It just doesn't walk the talk.

Today I had to fill my tank again. It's been 185 miles since filling last and had to put 14.2 gallons Mobil 93 Octane in it. 13 MPG. I have my dealership contacting the Mazda Technical support to look into possibilities, because they won't take a look at the cat without a code being set. Oh, and I don't beat my car, redlining all day everyday. When I said driving it like a granny, I was simply saying that I pretty much didn't take it over 4k for a whole tank, which only got me 20 extra miles. I drive it like a "granny" and a sports car and everywhere in between now. All of it equally divided between hwy and city driving. I will fill you all in on the conclusion if it ever happens, lol! I love this car though and so do the ladies, lol!

I hear ya. Your driving habits really seem to have no effect on the outcome of the overall mpg. I can redline every time I drive and floor it at every light and get as good mileage as I would shifting at about 4-5k every time with one redline a day.

But yes, the ladies really do love this car. I was leaving a friends house and 2 chicks saw me drive off and later that night I got a phone call from my friends sister saying the girl she was with wanted my phone number.

I had an RX8 for a year back in 2004. I traded it for a 2005 G35 coupe which I recently dumped in favor of a VW Jetta 2.0T. Vee Dub Yalll. I get 25mpg in mixed city/fwy and 32+ on highway only. I made a 130 mile round trip to a golf course recently on 1/4 tank. I can hit 60 in under 7 seconds and have great driveability around town since the turbo spools so early. I get peak torque (207 lb ft) from 1900 to 4500 rpm! I miss my Rex at times but not at the pump. The Jetta might not have the sex appeal of the 8 but it is a damn solid car, performs well, doesn't cost as much to drive, maintain, insure, replace tires and came in way less than an 8 with GT package (I was out the door for $22,199). If mileage is such an issue, there are other vehicles out there. Don't get me wrong, I was a big fan of my 8 and defended it agressively against trolls on this site and other miscellaneous haters but damn, there are alternatives. Factory turbo cars are hard to beat.

P.S. I can get reflashed aftermarket for 30 more hp and 40 lbft on pump gas for $595.

P.S. I can get reflashed aftermarket for 30 more hp and 40 lbft on pump gas for $595.
Perhaps, but there goes the "doesn't cost much to maintain" part. If you think a 15% hp and torque bump won't cause any reliability problems... Well, good luck if you go through with it. VW is smart enough to figure out if you've done a reflash and will deny any warranty claims if they catch you. :(

Not 'haytin' on Veedubs, I had a Jetta for years and still love 'em... But perfect they ain't. Their reliability in any recent year you wish to name is near the bottom of the barrel and the new Jetta, sad to say, looks like a Toyota. I'd probably get another Mazda6S before I'd get a new Jetta. The only thing that the Jetta has over the now four year-old 6 design is a better-quality interior and better overall mileage. Can't wait for the new model next year, or more accurately, my gf can't wait for the new model next year, if it still offers the V6 with a stick.

Perhaps, but there goes the "doesn't cost much to maintain" part. If you think a 15% hp and torque bump won't cause any reliability problems... Well, good luck if you go through with it. VW is smart enough to figure out if you've done a reflash and will deny any warranty claims if they catch you. :(

Not 'haytin' on Veedubs, I had a Jetta for years and still love 'em... But perfect they ain't. Their reliability in any recent year you wish to name is near the bottom of the barrel and the new Jetta, sad to say, looks like a Toyota. I'd probably get another Mazda6S before I'd get a new Jetta. The only thing that the Jetta has over the now four year-old 6 design is a better-quality interior and better overall mileage. Can't wait for the new model next year, or more accurately, my gf can't wait for the new model next year, if it still offers the V6 with a stick.

Werd, it does look like a big corolla, a bit boring indeed. You're right about the 15% torque bump, it's not in my plans until the 5yr/60000 mile powertrain warranty is up. That new mazdaspeed6 is sharp, I'd drive one of those!

I did mean it when I wrote "sad to say". I like VW and wish they'd not mucked up the redesign...

.....I recently dumped in favor of a VW Jetta 2.0T. Vee Dub Yalll. I get 25mpg in mixed city/fwy and 32+ on highway only. I made a 130 mile round trip to a golf course recently on 1/4 tank. I can hit 60 in under 7 seconds and have great driveability around town since the turbo spools so early. I get peak torque (207 lb ft) from 1900 to 4500 rpm!.........


but its a Jetta... :dunno: Just out of curiousity, why did you trade the G. The only reason I can think is $$$$$, those things are expensive!

Update. I WAS getting 14mpg with what I would consider normal driving. So I started shifting at or just below 3000rpm, but still redlining it every so often when I want to have fun. My gas mileage has skyrocketed. Normally at 40 miles I'd already be down a 1/4 tank. Now I'm at 82miles on this tank and it just dropped below the 1/4 tank mark.

That's like my driving. I filled up yesterday and calculated out my mileage on my last tank and got 24.18. I was happy. I have broken the 24 mark twice now. :) Otherwise I average around low 23s. I have mixed driving. Downtown stopping every block. Crappy highway rush hour where you move at about 15 mph and then hit the brakes about every 20 feet or so. LOL It takes me an hour to get to work and at least half of it going 30 mph or less and/or stop and go because of bad traffic. I save about 15 minutes on the way home since traffic is pretty light and I don't have the rush hour stop and go. My last tank I was right about 90 when it dropped below the first 1/4 down mark. This tank I only have around 20 miles on it so it is still right up at the full line or just a tiny bit under.

I always put in Chevron Supreme which is, I beleive, 92 octane here. The two times I have used Shell V-power my mileage dropped into the low 21s and my car didn't seem to run as smoothly and seemed a little sluggish. I haven't tried any other brands. Bella just seems to love Chevron!

Edit: The two times I got low 21s also, coincidentally, happened to also be when my car was at the body shop getting the rock dent fixed on the hood and then when I brought it back in at a later time for my complimentary detailing. I told them to make sure not to shut the car off cold and taped a note to the steering wheel.

Not 'haytin' on Veedubs, I had a Jetta for years and still love 'em... But perfect they ain't. Their reliability in any recent year you wish to name is near the bottom of the barrel and the new Jetta, sad to say, looks like a Toyota. I'd probably get another Mazda6S before I'd get a new Jetta. The only thing that the Jetta has over the now four year-old 6 design is a better-quality interior and better overall mileage. Can't wait for the new model next year, or more accurately, my gf can't wait for the new model next year, if it still offers the V6 with a stick.

I've got a 2004 Jetta GLI (the limited edition with the body kit, BBS 18" wheels, polished stainless steel exhaust, Audi TT brakes, Recaro seats and 6 speed manual transmission) with 40k on it in two years of ownership. Zero defects. None. Nada. Zip. Zilch.

Also does 28 MPG at 75-80 MPH through the AZ and CA deserts...

The wife doesn't care for the new Jetta design though. Not aggressive enough!
Eric

Oh oh gotta toss in my two cents on this one.

lowest avg so far has been 10.5mpg but that was me doing a high spirited drive from Northern VT to the South Shore of MA.

So far for a 4 week period I'm avg 13.09mpg. Highest I've seen since owning is 13.61 and that was within my 4 week if you will test of mileage. All tanks fit in around 13.25 gallons or more give or take another .25.

I'm not bitching just had to toss my 2 cents in. Though I almost did flip out about the 10mpg tank till I realized the slip was from my Vt trip back. Thankfully gas is starting to go back down around my area so its a bit easier to swallow, just wish it was atleast 1.50 then I'd just shrug off this bad mileage all together.

3rd grade math is pretty hard.

That's why some people measure by the tankful.

why is it that gas mileage threads are always sooooooooooooo long?

And there's also people that just post about 3rd grade math over and over and over as if everyone does MPT even when they very directly have miles and gallons in their posts.

I get 14 MPG done the 3rd grade math way (tm). I am suddenly getting better economy on the last two tanks and am trying to figure out why.

What I'd really like to see is two RX8 owners that live near one another and get opposite ends of the spectrum trade cars for a tank or two. We really need to figure out if it's the driver or the car.

I got 24.1 mpg on the last tank. Of course it was 95% highway at 75-80 mph. And I only have 13,000 on the odometer.

This is a long shot, but… could there be more variability in reported mpg (compared to other cars) because it's harder to calculate exactly how much fuel you've used in the 8? Sometimes I think there must be something different about the 8's filler tube or something that causes the pump to first "click" off at a different level each time.

I fill up at different gas stations (like I have with other cars), and I stop pumping at the first "click" (like I have with other cars), but with the 8, I get the feeling I'm filling up to a different point each time—which would make my calculations off a little. (I'd love to make it easy and just "top it off" to know I'm really filling the tank, but that's not good for the emissions controls. So I use the first "click" as a reference to stop fueling. But what if that first "click" is, say 15.2 gal at one station and 13.3 at another??

What about you guys? If you calculate mpg traditionally (miles divided by gallons), how do you know how many gallons you've used?

I really doubt that one station clicks off at two gallons away from another one. That's 12% of your tank! Those fillers detect when the liquid comes up and touches them, and the filler is thin, so what it basically means is that the fuel has backed up into the tube. The tube doesn't hold gallons.

Even if you assume a 10% difference in fill ups, that doesn't fix the HUGE range of numbers reported here. We have people saying 12MPG and those saying 22 MPG. Well, adjust each one up and down 10% and you get 13.2 MPG and 19.8 MPG. That's still a 50% difference in cars or drivers.

Also, averaging over a few tanks is always more accurate. I know that I always get right around 14 gallons into the tank after the light comes on, so it's not like there is much variation, and if you keep track over 5 tanks it's not like you manufactured gas at some point. It's only the innaccuracy on the last tank that factors in.

I see—didn't realize the filler is so small and insignificant. Thanks for the info!

What about you guys? If you calculate mpg traditionally (miles divided by gallons), how do you know how many gallons you've used?
I usually top off with another .3gals after the pump clicks off.

Remember that the error introduced by the variability of top-offs really only applies on single-tank fillups. If you keep track over several tanks, or ALL tanks in my case, that error is effectively zero if you're dividing the total amount of gasoline pumped into the car over the total mileage.

get it out on the highway and FLOOR it. Keep it in 3rd if you have too and run it over 7K for a while.

change gas stations. use quality gas.. the cheap shit is just that. 87 gets me better milage. good 87 is better than cheap 93.

I'm a good 50/50 of city highway and I always get about 22 mpg, more on the highway, but you really have to run the car and keep it happy.

if you still have crummy gas mileage one more thing to try.. after driving. park, go into nuetral and rev then engine, hold it steady at 5k or so until the car gets hot, you want the temp gauge to start moving, or to hit the too hot fuel cut. make sure your thermostat is working. if it's sticking it can kill your milage.

I agree. This car is MADE TO BE PUSHED.
I don't know what your idea of "low rpm" is, but that could be what's killing your mileage.

Added, later:

Okay, okay, sorry in advance. This has already been addressed in this thread.
I didn't want to delete my post though. I just LOVE this dang car!! And, love to read & talk about it. It's a passion.

And all that is with me purposely driving like a granny. Can't imagine if I almost redlined it alot, lol! Probably get like 10 or 11. Oh well, I still love her.

If you love her, REDLINE HER. She needs it, wants it, craves it.
She is made for it.

once again, {{{{{hmmmmm}}}}}}
Thank you guys for not thinking I am a sicko.

hehe.

BTW, when I drive, I vary greatly from shifting at 1.5 rpms to 7K rpms, to doing 50+ in second gear.
But, I ALWAYS get 260 miles per tank. Unless I have had a really crappy errand week. At 260, that's when the light comes on.
I don't worry about the calculation, because I know 260 is good. I don't care how good or if it's a little off, I expect some variation.

Actually, pre-detonation is a lot worse for a rotary engine than a piston engine. Rotors can often by destroyed by just one bad knock.

Okay, okay, okay, I give. Someone please explain "Pre-Detonation" PLEASE.

Here are things that I come up with to improve your RX-8 gas mileage:

1. Verify your calculation point. Are you running the RX-8 all the way dry or are you re-fueling when the yellow light comes on??? If you are waiting until the light comes on, than you may still have 1 gallon to 2 gallons of fuel left (so you may have used 13 or 14 gallons as oppose to 15 gallons). Don’t make the mistake of calculating that you have run the tank dry from that point when you do the math.

2. Check your oil? Changed your oil filter? Are you in a hot climate? Think about getting the fan mod? How many oil coolers do you have?

These are important, because they seem to be factors. I changed my oil filter from the oem one to a Mazdaspeed oil filter and picked up 1-2mpg. I had been checking and adding oil, but remember to change the oil filter at the designated time. Actually, you may want a high performance oil filter while you are at.

If you are in a hot climate, there appears to be issues with temperature. A 2nd oil cooler (if you have one of the ones that don’t have it), fan mod (search for Looking for a cooler running RX-8? Or go to http://www.mazsport.net).

3. What is the octane level of the gas you are buying? Who are you getting your gas from?

The RX-8 likes 91 Octane or better gas. If you put in lower octane than you are supposed to than that may be the reason why you are getting lower than expected gas mileage. If you insist on using low octane gas to save money, than consider at least adding an octane booster. I’ve used octane boosters with Xylene, with great success. Xylene also burns well, without leaving a lot of deposits, like other octane boosters.

Note/Edit- There seems to be some debate about which is the better octane level. It seems higher Octane is better for performance, but maybe not for gas mileage. Lower Octane, but high enough not cause knocking, may be better for gas mileage. I think the best bet is to stick with Mazda's Octane rating when in doubt, but experimenting with different gasoline from different vendors and with different Octane ratings may help or show something.

I’m getting better gas mileage when I fill up at certain gas stations. I’m not clearly understanding this myself, but it appears the additive package from different gasoline companies are… different. Thus the RX-8 performs better with gas from certain gas companies. I think you need to test this on your own, as oppose to me telling you who to go to and this may vary from state to state or from country to country.

4. You need to rev your RX-8 to at least 6K every day/every other day (higher for the M/T). Have you been doing this?

Some people are babying their RX-8 way too much. This can be hurting your engine, as oppose to helping it. The RX-8 rotary engine is different. Consult this forum or your user manual (just good to read anyway) for more info.

I’ve also seen some more specific advice in this forum, but I’m having trouble locating it right now, but soon as I do than I will let you know. But the above would be a big start for people having trouble with their gas mileage.

More....

5. Check your MAF ( Mass Air Flow) sensor/meter. Here is a link to a part for cost estimate and a reference.... http://www.drivewire.com/mazdaparts/catalog/mazdarx-8airflowmassmeter.html

6. Check your Catalytic Converter. It appears that its possible for them to become clogged or damaged in various cases without the a CEL light going off. This can be the cause of an RX-8 eating too much gas or not accelarating "properly", so should be checked by an Mazda dealer.

7. Check your PCM (Powertrain Control Module) / ECU (Engine Control Unit) . It may need to be re-programmed/flashed. It may be injecting too much fuel when your engine is started an causing carbon build up and other issues. It appears that various RX-8 have problems with their ECU / PCM.

Note- results of having the ECU / PCM flashed appears to vary.

8. Check Air Filter or consider buying Cold Air Intake. May improve gas mileage.

9. Check O2 sensor. Could be responsible for overly rich mixture.

10. Another factor worth mentioning is customer expectations. The RX-8 is a sports car. Gas mileage in most sports cars SUCK. You should expect 17 to 24 MPG from the RX-8 and most other sports cars. I think RX-8 users complain a little more, because the price range and the “cool factor” means people buying the RX-8 might have bought an economy car, but choose the RX-8 after looking at it. These same people that are used to a 4 cylinder econo car then have a hard time understanding how to take care of a rotary engine or anything that will get less than 25 MPG. Well, the RX-8 is for FUN. If you don’t want a cool looking and fun to drive sports car, than go ahead and get an econo box and call it a day. Otherwise, I say, go over a list of thing that may be causing poor gas mileage in your particular RX-8. Also, see your Mazda dealer and make sure they check and confirm that there is nothing wrong with your car.

thanks for the info sosonic! very helpful!!