Since day one, 3,900 miles and 3 months now, I have averaged 10 to 12 MPG in the city and 17 to 19 on the highway. Mazda claims 19 and 24, respectively.

Dealer says it is normal, but I just don't buy it. They say there is nothing they can do about it.

Anyone else getting terrible fuel economy? Any suggestions?

I have ~800 miles on my 6MT. 1st 3 tanks of mostly city
driving gave these results:

1. 18.4 MPG
2. 18.6 MPG
3. 19.1 MPG

I've not been on an extended freeway drive yet but suspect
it'll get a couple MPG better.

Rgds, Mark

Do a search on here for "gas milage", you'll see that TONS and TONS of people are getting ~12mpg city. I get ~11.5-12mpg in the city also.

There are a few threads which recommend contacting the NTHSA and a link to their site to complain.

-- Aaron

Will,

Lots of posts already on this subject. Keep in mind the numbers on the sticker are the goverments, not Mazda's. not defending poor little Mazda, just trying to clarify. My milage numbers are close to yours, but have you added in the fun factor? Always makes that issue go away for me! :)

Not to be mean or anything but if you did your research before you bought the car you should have known about the gas mileage issue. It has been talked to death on this forum. I personally knew about this issue and I still bought the rx-8 knowing what was in store with gas mileage.

I realize that rotary engines are typically gas guzzlers, but the whole point of the Renesis engine was to have much improved efficiency and power over the last series used in RX-7's...at least that's what I've been reading and hearing.

Premium gas around here is $1.80 these days. That coupled with 10.5 mpg (last fill up) is breaking the bank!!

Granted, the fun factor is nice, but there just aren't that many opportunities really enjoy it, thus, my conservative driving habits around town should give me better results than 10 to 12 mpg...shouldn't it???

Conservative driving is relative...I average 18 MPG - 60% city / 40% highway. Traffic keeps me from driving too hard so the majority of my shifts are at 4 - 5K RPM. I cruise in 5th or 6th gear and don't hold revs too long.

This car hates idling at red lights more than anything...

...Not to be mean or anything but if you did your research before you bought the car you should have known about the gas mileage issue...

I did a ton of research and the places I checked out all quoted Mazda's claim and said that the claim was fairly close according to their tests. Unfortunately, I did not find this forum until months after my purchase.

This car hates idling at red lights more than anything...

Does yours vibrate at idle? Man, mine sure does. It's very irritating to say the least. It just started this and seems to have gotten progressively worse. I'm thinking fouled plugs. Oil level is right on the mark. (I check it at every fill up. I've added 3 qts. in the first 3,500 miles.) However, give it just a tiny bit of throttle and it's smooth as silk and remains so up to redline.

I haven't had time to paruse all the threads, are there any threads on this subject?

3 qts in 3500 miles!!! That sure sounds like a lot, are you driving it fairly hard? I'm at 2200 and have added less than 1/2 qt.

Maybe a trip to the dealer for a check up wouldn't hurt.

3 qts in 3500 miles!!! That sure sounds like a lot

Doesn't it though?! The service mgr. told me to expect it to use 1qt/1000 miles. Reason he says; because there are 4 oil injectors that inject oil directly into the combustion/intake area to lube the wipers against the rotor wall. He claims that there is no other way to get oil in this critical spot and because of where it is going, naturally it will be consumed over time.

For the most part, I drive "normal"...just staying with the traffic flow, not a lot of high revving. But being what the car is, one can't help but put their foot into it from time to time! :-) I've heard the rev limiter "buzzer"...well, more than once, but certainly nothing to warrant excessive oil use.

am on 4th tank.

tank 1 18.4mpg
tank 2 20.2mpg
tank 3 20.8mpg

about 70% highway

tank 4 is not going to be pretty just hit the 1000mile mark and drove very very hard yesterday. this car is awsome and the brakes are increadable.

beers

Originally posted by Will Barger
Doesn't it though?! The service mgr. told me to expect it to use 1qt/1000 miles. Reason he says; because there are 4 oil injectors that inject oil directly into the combustion/intake area to lube the wipers against the rotor wall. He claims that there is no other way to get oil in this critical spot and because of where it is going, naturally it will be consumed over time.

For the most part, I drive "normal"...just staying with the traffic flow, not a lot of high revving. But being what the car is, one can't help but put their foot into it from time to time! :-) I've heard the rev limiter "buzzer"...well, more than once, but certainly nothing to warrant excessive oil use.

what the service guy said is correct about what,when, how and why of oil usage in the renesis engine. however on the quantity he is way off. no one on this site has ever mentioned using the amount of oil you are. most people i believe are adding about 1 quart per 2,500 miles. if that much. your oil consumption is wrong. have them check it out. period. also you need to have them re-flash whatever they have to, to try and fix your mpg. if you are simply driving like a normal everday driver just around town (sort of "granny driving") there is no reason for you to have had 10.? mpg unless you can't calculate it correctly or there is something wrong with your engine and/or its computer. hell i ragged the crap out of my car for a full tank recently and got 12.2 mpg. there is something wrong with yours.

Zoom44,

I agree with what you are saying. I certainly do not want to come off as "bad mouthing" my dealer service mgr., but he admitted to me that neither he nor anyone else there is up to speed with the RX-8 in general. They constantly compare the '95 (9 year-old) RX-7 to the 8, which is just wrong. He claims that they have no way to modify the 'puter nor anyway to read engine data...as of yet. ??????!!!! To be such a great dealership and the largest Mazda dealer around, you'd think they'd be state-of-the-art.

When I park in my garage at night, the entire garage overwhelmingly smells like raw gas. Smell the exhaust tips and there ya go. I mentioned this to them along with all the other symptoms and they said it was normal. BS!!

...and BTW, Let's see...I drove 125.7 miles and put 11.9 gallons 'til you can't sqeeze another drop in and if I am correct, that comes out to 10.5630252101 MPG...hehehe ...oh, and at 1.799/gal, that cost me $21.41 ouch! We engineers have to know a little math :-)

will barger,

what is the build date of your car????

just curious.

beers

Wow soyou guys w/12 mpg city cant even get 200 miles out of a full tank? I thought I hadit bad. I at least get 240 in 100%city driving. Will Barger is your car auto or manual? I havethe idle problem too go and read this entire post http://www.rx8club.com/showthread.php?s=&threadid=17611

sorry, no slight intended. we have seen a few people who have not calculated the mpg correctly so it helps to ask. is there another dealership close to you? if so go there. tell them everything that you told the other service department and make sure they know they are the second to look at it. tell them everything the first guy said. if there is or isn't you need to escalate this to a regional service rep. get someone to make the call because if first service guy doesn't have the means to flash your comp he should. plus you need to get someone in on this that has actual knowledge and training. also check the tsb's in the sticky up above this one and print them all out and take them with you so you can make sure to have whatever work is required done.

Not exactly sure...do these photos tell you?

http://www.willbarger.com/rx-8/hood.JPG

http://www.willbarger.com/rx-8/door.jpg

swoope,

the photos were for you...

sorry, no slight intended

Absolutely none taken.

yep those will do. your car was born in august of '03 and you can your vin there against the vin ranges for the various tsb's to see if your car is affected by any of them.

JeRKy 8 Owner - is your car auto or manual?

6 speed man.

Thx for the link!

Originally posted by Will Barger
Not exactly sure...do these photos tell you?

http://www.willbarger.com/rx-8/hood.JPG

http://www.willbarger.com/rx-8/door.jpg
yep,
and the build date was given correctly. has anyone looked at the idea of the eairlier build dates tend to get bad gas millage.

i also notice that the west coast tends to be worse.

i guess i have been lucky i knew about the gas mileage going in. and it is close to what i hoped.

i do find shifting before 4k helps.

my build date was 10 03

beers

Do a search, there is a thread that included details of each persons car and avg mpg. It did appear that vin#/date of mfg had little to do with mpg.

That thread is called " Lets compare Vin# and MPG" I don't know how to post the thread link here.

How do you do that?

On saturday coming home from Reno (220 miles) using cruise control at 3500 RPM I averaged 25.3 MPG. This was with the first 40-50 miles being in terrible snow and ice. The rest of the drive was very relaxed with good driving conditions. I think I would have got 27+ had it not been for the first 40 miles.

In the city I get 17-19 depending on how hard I drive it.

Originally posted by swoope
yep,
and the build date was given correctly. has anyone looked at the idea of the eairlier build dates tend to get bad gas millage.

i also notice that the west coast tends to be worse.

i guess i have been lucky i knew about the gas mileage going in. and it is close to what i hoped.

i do find shifting before 4k helps.

my build date was 10 03

beers

Im interested in the build date theory, but I think the reason the west coast may get worse gas mileage is because we have alot of hills to climb.

thx

and i dont know. lord know whats going to happen if i figure out how to post a pic or make an avitar.

beers

http://www.rx8club.com/showthread.php?s=&threadid=12965&highlight=Lets+compare+Vin+and+MPG

searay i figured it out, just cut and paste the address window into the thread.

beers

It shouldn't be idling rough. How bad is it? Is the whole car shaking or do you feel it in the shifter only? If you feel it throughout the car I would definitely take it in for service! It could be fouled plugs or a vacuum line problem! check all your lines and connections around the air intake tube! Or it could be the dreaded engine failure that a few people experienced with similar problems (rough idle. poor mpg) as yours. I'm not trying to scare you and hopefully it's and easy fix, but you should bring it for srevice immediately,good luck!

Build date on mine is 05-03. I bought it 12-19-03. Only 750 miles so far but filled up today - 9.9 gallons at 159 miles. All of it city driving (and we got hills too in East TN). And I don't baby it either. Lots of short trips (5 miles or less). Longest drive yet probably about 50 miles.

10 mpg is abnormal and you should pester your dealer. I generally get 16-18mpg under normal circumstances and the lowest I've got (following the breakin) is about 13 and that was over 100 miles of *very* hard driving. I find it difficult to believe they can claim 10mpg is normal while holding a straight face... My car is a June 2003 build date .. vin is 019xx

It shouldn't be idling rough. How bad is it? Is the whole car shaking or do you feel it in the shifter only?

Let's just say this, while sitting at a traffic light, etc., idling, I won't rest my head on the head rest 'cause of the vibration. It started out just in the shifter...which I think is normal, but now, things inside the door rattle, the seats shake...etc., but only at 800 rpm idle speed.

Nope, that's not normal. Take it in for service ASAP!

Not that I'm bitching about poor gas mileage or anything......anybody who has done that on this forum just gets on my nerves. GO BUY A TOYOTA PRIUS OR SOMETHING if you are pissed about the poor fuel economy!

My 8 is averaging about 16-19 MPG with about a 50/50 mix of city highway driving. It is not driven hard because I'm usually always right behind somebody. :(

My old 1991 RX-7 convertible with 95,000 miles on it gets about the same MPG as the 8 does, and it weighs MUCH more than the 8 does. I feel that Mazda did a pretty good job with the Renesis when it comes to the amount of power gained from its design over the old rotary while maintaining the fuel economy.

Originally posted by 91vert
Not that I'm bitching about poor gas mileage or anything......anybody who has done that on this forum just gets on my nerves. GO BUY A TOYOTA PRIUS OR SOMETHING if you are pissed about the poor fuel economy!


Except that 10MPG is not just bad gas mileage being complained about, it's abnormal and likely indicates something wrong with the car. As such the owner should complain (but not to us) about it and pressure the dealer to diagnose and fix the issue, or replace the car. It could be something as boring as a bad thermosensor keeping the engine running in an enriched mode cause it thinks it cold all the time.

Folks getting 10MPG consistently should not just moan about bad mileage and do nothing about it - it just proliferates the gloom/doom of rotary=bad mileage - I mean hey, the car does get low mileage but not that bad.

Simon.

Will,
Your 800 RPM idle speed seems low to me. Mine idles at 1,000 when warm. You say that it smooths out if you give it just a little pedal which probably puts it near 900-1,000 RPM. Has it always idled at 800 RPM (even before this started)? Almost sounds like a loose vacuum line, or something getting jiggled loose when checking the oil, fouled spark plugs, etc.
Smelling gas in the garage after shutdown is a definite no-no with some serious potential for unpleasant consequences with all the hot parts.
Low idle speed will have a definite impact on fuel mileage as well. Plus, you are probably having to fiddle with the gas pedal to keep vibration down, and then over-rev starting from a stop to keep from killing it. Any of these will degrade fuel economy. All of them combined will really impact it. I would definitely go back to dealer. If they give you the same song and dance, then find another dealer or call Mazda customer service.

Originally posted by 91vert - Not that I'm bitching about poor gas mileage or anything......anybody who has done that on this forum just gets on my nerves. GO BUY A TOYOTA PRIUS OR SOMETHING if you are pissed about the poor fuel economy!

Dude! Did I strike a nerve???

Except that 10MPG is not just bad gas mileage being complained about, it's abnormal and likely indicates something wrong with the car.

That's exactly the point...thanks Simon. I will check for loose hoses, etc. Who knows?

...you are probably having to fiddle with the gas pedal to keep vibration down, and then over-rev starting from a stop to keep from killing it...

Exactly! Esp. the over-revving when starting from a stop. It always luggs wants to die. Quite frustrating...but what's even more frustrating is convencing the dealer service dept. to do something about it without confrontation.

I have a new 2004 RX8 I didn't caculate the first tank but did do the second. I filled it up and at 202 miles I filled it up again, it took 12.37 gallons which is 16.33 miles per gallon. I drive it pretty hard and all has been in town no highway miles. I also park it in the garage and there are no gas smells. I will be going on a 400 mile trip to Florida and will keep you posted as I collect the data.


2004 Winning blue RX8

Will,
Take it to the dealer and have him ride with you (not just talk to you) to show him what it's doing. Stop before you get back and have him drive it back to dealership with you in the car. This will either convince him there is a problem, or help identify anything you might be doing to bring it on. I doubt you are doing anything to cause it idle rough, but sounds like the dealer needs an attitude adjustment and sometimes you just have to demand their attention in order to get it.

My values :
13.2 MPG in city center (17.8 l/100km for european readers)
24.5 MPG outside city (9.6 l/100km)

What Will Barger is saying about the dealers is correct. Mine told me they are "still on a learning curve with this animal". At least he is honest. My wife was getting 10 mpg in town and maybe 15 on highway. She is a "granny driver". I complained to the dealer and he did the following.
Replaced the plugs with the hotter ones. This eliminated the "ticking noise" and engine vibration at start ups.
He then spent the next 3 hours with the portable phone in his ear and under the hood & inside the car whild Mazda walked him through Re-flashing or Re-programming whatever part it was. It took multiple tries before it was done. The result is now almost 15mpg city and 19 hwy. She usually drives 75mph on the highway so I can live with that. We have very different driving styles so I never see the milage she is getting but it did increasewith my driving style too .