JeRKy 8 Owner

I read on here that the car is supposed to get better mileage after 2000 miles. OnThursday I drove the car all the way to empty so that I could have a freshtank after getting the car up to 2000 miles and then I filled the tank up fresh. I reset the trip meter tokeeptrack of my miles. You guys remember I have an automatic not manual and I only do city driving no highway. Well Now its late Saturday night and I have driven156 miles on this tank from Thursday to now and my tank is already down to 1/4 full! Its still the same crappy mileage that I wasgetting before 2000 miles man. Im already at 2200 miles and Im not even getting 15mpg. Somethingsvery wrong here. Its all city driving and I drove it hard only twice since Thursday to beat two redlights. Im making sure the car is always in 4th gear but I guess nothing is helping here. Im not very happy about this guys! Should I take my car in to Mazda or arethere other people here w/more than 2000 miles that sitll get bad mileage like me? I thought this was going to finally go away!!

8_wannabe

Seems like there's too many variables for us to figure out exactly what's going on. I am concluding each car has a "personality" of its own as no two seem to behave alike. Mine did improve after 2K from ~ 15 mpg to 17-18. Many people have been in the low 20's all along no matter what they do. Go figger. This is my #1 gripe about the car. The only reason I kept it despite being eligible to return it is I believe someday it'll be fixed. I think Mazda and maybe some aftermarket folks will find a way to improve mpg while not giving up too much power and still meet EPA specs. I don't know any of this for a fact but I do believe it.

RX-GR8

this is not good. maybe your ecu was not reprogrammed correctly at the port.

mikeb

you could have dealer check it out

mngpao

I've had my RX8 with AT since Aug 23. With 50/50 city/hiway I've been getting about 21mpg.

I now have 1500+ miles on it. I took a 303 miles drive which took 12.5 gallons to fill. That works out to 24+ mpg. It was 95% hiway driving with speeds mostly between 50 and 60mph.

Since the AT is supposed to get 18 to 25mpg, my RX8 seems to be right in there.

I've noticed many postings (in this and other forums) where people are only getting 13 to 15mpg. Either they are heavy footed or their RX8 should be taken to the dealer.

astrlsrfr

Hogwash. Dealers don't have a solution for this issue. Many people have contacted their dealers AND MNAO. Its already been established on this very forum that its NOT people's driving habits. Do your homework before making blanket statements.

I am over 2k & my mileage remains a crappy 12-13 MPG. If I am all highway, I can stretch out a mindbogglin 15ish MPG figure. As you might have guessed, my car is going back. I remain bullish on all the other outstanding qualities of the 8, & will gleefully buy another, brand new RX-8, once its been established Mazda has got their sheet together.

8_wannabe

thank you for setting the record straight, astrlsfr. You took the words right out of my mouth. With all the raw data we've seen establishing no discernable pattern I think one thing we've shown is that driving habits have only a small effect on gas mileage. There is still some unknown variable, which I attribute to something in the car, having the greatest influence on gas mileage. I suspect Mazda did some ECU reprogamming in haste and didn't have time to either standardize it nor assess all the impacts of their reprogram. I wonder if we need to try and drag the EPA into this for those deviating dramatically from the EPA estimates.

Spin9k

Sorry to hear you're sending your 8 back. Such is life. With over 2,000 miles on yours, you've likely filled up about 8 times, using a (high for you) 15mpg average.

Can you share with us the tank by tank numbers: You know, like this, so we can puzzle over it? Here are mine, for example, after picking it up with a full tank on the 18-JUL, about the same day you did.

DATE MILES GAL MPG
26-Jul 233.5 12.901 18.10
3-Aug 253 12.777 19.80
14-Aug 251.2 13.74 18.28
25-Aug 245.8 13.7 17.94
6-Sep 243 13.89 17.49
11-Sep 150 8.104 18.52
22-Sep 235.8 13.35 17.66
3-Oct 242 13.4 18.06

overall 18.23 mpg @ 1854 miles

AvitalBlue8

I'm getting 15 MPG(13 MPG once but that was because i was helping a friend with stick that envolved a lot of idleing), but i have a very heavy foot shifting between 6k and 8k.

Just passed 1k on the odo. This next tank i'm gonna take it easy and see how much i can get out of the tank.

hoffa

dude i get like 160mpg...what is that like 11? i live in a small city so lots of lights, and stops...most i drive consecitively is like 10miles, and thats to school..also the temp is usually like at 100F daily, i live in laredo texas..small city. also i use to get 160mpg, and after 2000miles i now get around 180

JeRKy 8 Owner

I didnt do alot of driving in the Rx8 today but I know my tank is going to be at empty when the tripmeter reaches 200 miles tomorrow afternoon. That tank is not even gonna be 14mpg guys. I looked at my dipstick today and the oil is not on full anymore its in the middle. Maybe I should try toget my oil changed to see if that helps my mileage??? Thatsounds stupid but amybe it will work

hoffa

u think since i live in a very small town..it affects me more? since all the lights?

RX8by

If you look at the posts here the people compaining of low milleage are all from Hot climates. Maybe they reprogramed the ECU and it over fuels the car in the heat to cool the engine. Try putting 35 psi in the tires it will help.

LightEmUp

I just passed 6000 miles and I'm getting roughly 19 mpg. Like many people have said before, it varies from case to case. Elevation, temperature, humidity, how you drive it, etc...

8_wannabe

So what do people think of the '8 in Laredo. They must think yer some kinda hippy escaped californian or something. But I think you mean mpt (miles per tank) not mpg unless you've made some kinda hybrid car.

o_town_racer

Hey Spin9K. I've got a 1SP 6MT and my mileage is almost exactly what you're getting. My average is 18.5 to 19 MPG with mixed city/highway driving. If I leadfoot the tank, it drops to around 17 MPG. I'm taking a long highway road trip (Orlando to Atlanta) in another week and will track the mileage all the way. I'm hoping to get in the low 20's averaging 75 MPH on the highway. We'll see.

Peakster

Spin9K, can you please share with us math-challenged folk how you figure out those numbers exactly? I've only filled up once, and here is the way I did it: When the light came on at 228 miles, I figured there were two gallons remaining. Thus 228/13.9 = 16.4 MPG. Thanks.

B-Nez

Rgr that - I'd been getting average of 17 mpg here in FL. The first day it got cold (below 60F) for my morning drive, I managed a 19.8 mpg! Unfirtunately, I've been driving during the warmer times since - and yes, I rev the crap out of this car!

O.R.A.

The light is not that accurate. It could come on with 1 or 4 gallons left, depending on the car, road level, etc.

When you go to the station, note how many gallons of fuel it took for the tank to fill up and use that number.

mngpao

astrlsrfr:

re your "hogwash" response...

I did a little "homework" as you stated. I'm finding that many people who are getting poor gas mileage are "cruising" at 5-6k rpm.

I've been getting my good mileage (with my loaded auto trans) by keeping the speed between 50 and 60 (as per the speed limit signs) which puts the rmp at about 2500.

Do the math - if you cruise at 5000rpm your engine is going to use more gas than mine when it cruises at 2500.

stangmatt66

With 600 miles on the odo I'm getting 15mpg. Pretty bad for such a small car, but I keep vigil that it will improve...

Also, out of curiosity when does everyone's empty light come on??? Mine turns on when I get to a quarter tank which is very conservative!

8_wannabe

what astrlsrfr (and many others) are trying to do here is stay away from anecdotal evidence that can mislead. Like, I drive with my headlights on and I get good mileage, therefore if everyone drives with headlights on then everyone will get good mileage. There is a lot of this nonsense going on here and is distracting us from seeing the real problem.

I appreciate you taking the time to research it but I think we still haven't gotten to the bottom of it. As you say, " many people who are getting poor gas mileage are "cruising" at 5-6k rpm." This is true. However, there are many people cruising at greater than 5K who are getting good gas mileage. And there are people cruising at 3K who are getting crappy gas mileage (me, for instance.)

This is what I meant in my earlier post that "we've seen no discernable pattern (but) one thing we've shown is that driving habits have only a small effect on gas mileage." Its very puzzling, we see conflicting data, and I don't think a single, underlying cause like RPMs has yet been found. I believe our cars are programmed differently and no matter what we do, we're doomed to either good or gas mileage. This is strictly my opinion based on anecdotal evidence (which I said I'm trying to avoid) but I see no patterns or trends that can support any other conclusion. This opinion goes back to the days of the first shipments in July that were mysteriously held at the Port of Entry for some unknown reason. I think reprogramming was done at that time, in haste, to meet EPA requirements and now we've got a variety of ECU programs among the RX-8 fleet.

mngpao

8-wannabe:

You are correct - I stand down.

If it is the ECU it seems that something could be done about it at the dealer sooner or later- yes?

energie

do you guys anticipate that Mazda will do somethin about this mileage problem? maybe workout some patches to the ECU program so we get better mileage.. I've read many of the posts, but im on the same boat, im getting abaout 350~380km per tank

jdl

Here is my mpg log.
For comparison, I also drive a 4.0L M/T 1993 Ford Ranger just as hard/conservative as the RX8, same routes, times -- hey, old habits and all -- and got 15.97 mpg on the last tank.
-jd.