If anyone is getting bad fuel economy even when driving like granny, you need a new engine. When Mazda replaced my engine, my city fuel economy went from 16 to 19-20. I wasted $1500+ on gas over 3 years because I had a broken car. If your economy is crap when driving nicely, or you have any other miscellaneous loss-of-power problems, tell your local mazda service people to stop screwing around and give you your new (refurbished/remanufactured) engine.

I'm going to write a letter to Mazda asking for reimbursement for the wasted money on fuel. Think they'll pay out?

 

I'll go back to normal after your PCM has some more drive cycles on it and you carbon it up.

There are quite a few of us that get well over 22 MPG now. Ask us how.

 

I drive and shift like a granny, usually around 3000 rpms, and i still barely make it to 200 miles on a tank. Most of this is city, with maybe one or two redlines, but that is still really bad mileage. I tried to get the dealership to do the carbon removal engine cleaner but they refused. Any ideas of what i can do?

 

do the carbon removal yourself for 20 bucks, less if you use seafoam

 

Cat saving cruse map = fuel burning map.

Chuck the cat, and cut out the cruise map that dumps fuel to cool the cat. You'll see fuel economy gains. AFAIK this is the only way to make real world gains on the car.

 

I wanna know how? 22MPG? is the answer really to ditch the CAT? If so, is it a lot louder without the CAT?

Tried to PM you MazdaManiac, but it says your box is full..

 

you can keep the cat installed and still do this, but the cat may not last nearly as long.

without the cat, the stock exhaust is still quiet. It's got a little bit more roar, but overall it's close to stock.

if you have an aftermarket exhaust AND no cat, it can be quite loud.

 

I got 269 miles to my last tank, and I ran out of gas 1 block away form gas station

 

yay another mpg thread!
but in all seriousness, i shift pretty agressively and will still see about 250 miles to the light. i can hit 300+ shifting conservatively...

 

i like watching my fuel needle go down as i idle. <lol>

 

idle is bad!

beers

 

23,700 miles can't be wrong. Can't mean I need a new engine. Just can't get piston-like efficiency.

Probably, those people who break rx8 gas records, they are the ones getting new engine first.

Should not be a big difference between speed racer and granny inside rx8... just 3 to 5 miles difference in range out of the whole tank from one driving style extreme to the other. Nothing to write an email home about.

My problem is, after break-in, the first 6 months of driving, I just redline 1st gear at every stoplight, every time. Now it is permanently drinking gas like that, I never got it to unlearn what it learn from the beginning.

 

not really.

depends on where you live. i am in the over 20mpg club. always..

but i dont drive in the city.. and temp does matter, and length of trip..

not as simple as i get 16 mpg..

i got 9.3mpg for a weekend. and it was big, big fun.. all about the content.

beers

 

my mpg gotten worst over the years, its been around the "same" right now for about a year.

I still remember I can get about 200 miles per tank (b4 the fuel light comes on), now Im having a hard time trying to get it over 160 a tank.

Plus all the weird idle issue Im getting ... new engine hmm ... Mazda's MSP16 flash came too little too late ? damage has been done ?

 

Mine has gotten worse over the years too. It actually feels good if I can manage to get over 200 miles on 1 single tank full now.

What's funny is when my engine losses power, my gas millage is better when it's limping, even with half to full throttle being used the whole time.

 

*shurgs*

I can afford gas, but if its really the engine dying that made me to lose few miles per gallon. I will be pissed.

 

I guess I should email you soon on the secrets on how to get 22MPG :D

 

how?

 

I used to do ~22 mpg stock with a cat. It's a matter of having a good compression engine and decent driving habits/high highway miles. Then, subtract the cat and get a cobb accessport tune and you do better. Keep your vehicle mass down, tire pressure high, and lose some rotating mass and you do better. I regularly do better with the a/c on low than with the windows open.

I've done over 20 mpg post turbo on the highway without being really dialed in on my tune. I'm doing around 16 mpg commuting (mmmm traffic + super rich idle) but my coils are also mediocre and on deck to be replaced. I can shoot some really wicked flames on coast down so I'm sure that isn't helping.

 

I did notice a drop in my MPG the last few weeks, I have to measure it the next time I fill up because something seems off. I have an 04, and the coil issue came up but I literally just had the car into Mazda about 3 weeks ago to have the coils checked, the plugs and wires changed, all the updating for warranty recall stuff. So Unless they just skipped checking and one of my coils is bad, I doubt thats it. Would taking the sub box out make a huge difference? Because that is the only change I have made to the car but I have yet to see that big a diff in any other car...

 

I had **** mileage a few months before my new engine. I saw in another thread you were fishing around to get that voltage test done, for reference, I failed with BARO 1.82 and IDLE 3.94.

pic related

 

I've had the car since it was new, and always got ~16MPG on the original engine. I've put 5k on the new engine and economy is getting better, not worse.

The original engine "passed" Mazda Service Dept's compression test at least 4 times before it finally failed. I don't have the test values.

To anyone dealing with loss of power and/or bad fuel economy, if your engine is close to the lower passing limit of their test, insist that the engine is on its way out and that it be replaced IMMEDIATELY. Otherwise you're wasting money on gas for no reason whatsoever. If they refuse, report them to the EPA for wasting gas

 

22...i guess if i drove the car nice i could get up there, but its not as fun!

 

I have about the same mpg as you, or maybe worst.

but they just tested out my engine and its fine, they actually replaced a bunch of stuff for me again, 4 new plugs, 4 new coils, de-carb. and they just did the same thing to my car about 3-4 months ago~

well, its a bit low but still within spec for now, I know they cant do anything unless it falls out of spec so ... just gotta wait.

*shurgs*

 

Yep, she drinks gasoline like a V8 in the city.