I get the worst gaas mileage. I have 2500 miles on my 8. The only mods I have have are a k&N typhoon intake and a greddy sp2 exhaust. My car has small backfires all the time and stinks like gas when you start it up. The absolutely best mileage I have ever been able squeeze out of a tank is 13 mpg. the worst is 10 mpg. Driving easy does not make much of a difference. I am getting the reflash done this week, I hope it helps. Can anyone lend any information as to what might be wrong with my car. Thanx.

 

Are you calling the popping noises from high revs backfiring?

 

yes I am

 

That is normal.

Your gas mileage on the other hand.... not so good.

Have you gone to the dealer for a PCM flash to version "M"?

 

yes, I am scheduled for this week. however they say it will not improve mileage. My dealership is not very knowledgeable and does not seem willing to help. I also heard that furel ports can get stuck open, is this correct. i guess I need to learn more about how this motor works

 

something else i forgot to note, my 8 is less powerful then the stock 8 that I demo'd last year

 

The M flash will help you, especially if you have one of the older versions on your car.

To be fair, most cars operate around 15-22 range. Some cars operate around 10, which is abnormal. Most of these cars seem to be one of the earlier batches, not sure if that is the case with yours. I haven't heard of any of these people being able to return the car for that reason though.

 

yeah, I love my car, it is almost too much fun to drive. But had I known that this would be problem with it, and that Mazda would be difficult to receive help from. I would have purchased a 350Z.

 

I'd also try removing the intake for a while after you get the flash.

 

why would that be, it is a pain, any reason

 

Prior to the M flash I was getting 15 or 16 MPG with "spirited" city driving. Now that I have the "M" I get 18 MPG. It definitely helps.

 

because you want to make sure that it is not the intake messing with your MAF that is causing your bad mileage. the only way to isolate the intake is to remove it and put the car back to stock.

 

m flash has no affect on mileage. it will not improve it. my gas mileage is the same before as it is after. i too suffer from 12-16 mpg tank in.. tank out. reguardless of my driving style.

 

I disagree, because I have definitely seen a difference. But as they say, "your results may vary."

 

It was posted elsewhere that perhaps cleaning the MAF with some rubbing alcohol (dip and dry) could improve your mileage.

 

Just had the M Flash today and the gas mileage is definitly better. The 1st to 2nd gear shift is smoother now too as it use to clunk at low RPM shifts. I swear baby feels significantly fassster now too!!:D ferreal.

 

The M Flash improve moved me from 18 to 20 Hwy to 20 to 23 Hwy and still is about the samein in the city at aroudn 15 to 17...

You will see a HUGE improvement in gas mileage at the 5000 mile mark. See my other post.... I have charts posted with accurate data.

 

No improvement for me after the M calibration.

My average is 14.38 mpg (75% city driving).

 

I have seen an immediate improvement in mpg.

see my post.

 

Your mileage will also vary depending on how you drive your 8. I notice that when I let my Dad drive my 8 sometimes, he cruises around 5000 rpm. He has been driving M/T forever but he doesnt understand when I tell him to just cruise around 2 - 3K rpm. You dont need all that power acceleration if you're trying to keep a speed. If you accelerate, even 4.5K rpm is sufficient enough. Just because this engine revs up to 9K, doesn't mean you should be using all ranges all the time. And besides, you have 6 gears to choose from. I usually cruise 45mph+ at 6th gear.

 

I didn't get any improvements in mpg after getting the M flash either. The car feels pretty much the same to be honest, and no matter how I drive, I end up always in the 18.1-18.7 mpg range - and that's with a lot of highway...

 

I don't know about the famous 'M' flash, but Mazda have addressed several issues with several different flashes. One was hard starting, the countermeasure was to lean off the air/fuel mixture at starting/idle. Another was fuel economy, the countermeasure being to lean off the mixture somewhere else (I don't have information on exactly where). Another was a hesitation at high load, where they increased the oil supply (to maintain compression).

As you can see, there are many fixes for many different conditions. How these effect your fuel economy is going to be very dependent on your driving habits, and also of course, on your individual engine. Cars are not computers, they don't all perform EXACTLY the same....

Like I said, I don't know what is in the M flash, but I wouldn't be surprised if it was "all of the above".

Cheers

 

Guys-my 8 born 11/03 so I am assuming has early ECU programing. I only have 600 miles on clock and last tank was all city driving and returned 14.8 mpg. Is this likely to improve with M flash?

Thanks,

Bob

 

DocBob, after my M calibration I'm still only getting about 13-14 mpg (75% city).



For those who have done this cleaning, should you expect to see anything on the q-tip? I just "cleaned" mine but didn't see anything on the q-tip. Just wondering... Thanks.

 

All of You with young RX8's that are stock will see a remarkable improvement in milage as soon as you hit 5000 miles! These are my charts which pretty much match up with what all of you are posting...





Notice at 5000 miles there is a remarkable imrpovement?