I traded my "01 A4 for an '04 M6 about a month ago and I love my new ride. One thing I wasn't expecting is that the gas mileage on the new one is running about 15 mpg tops whereas I was getting about 20 mpg with the A4 '01. I don't think my driving habits are that agressive (well...maybe a little agressive) and I'm wondering is there something I should check out regarding this?
Everything else about my triple black '04 vert is great and it's much more fun to drive. I know the shift points with the automatic automatically keep the rpms' down but I'm still a bit suprised at the difference. Any ideas on what I should look at, or is this normal?

 

You didn't really give much info, but that number sounds kind of low. My 04 Mn6 shows 27-29mpg when out cruising at highway speeds(65-75). It also calculates in the DIC that as an overall average, city and highway combined I'm getting about 19mpg. My car has light mods. I don't know what mods you have, there are a number of engine mods and drivetrain mods that could contribute to this. If this is your overall average and you drive more aggressively than me then your numbers may be fairly reasonable. If this is your highway average then barring some major drivetrain alterations you've probably got a problem.

 

With mpg that low, you are probably experincing extreme tire wear on the rear tires as well

I too get 27-29 whilst cruising at 75-80. City will be lower but my average is usually 19-24, that includes a few tire ripping take offs.

If you are doing mostly city driving and are keeping your foot in it, or you ride around in higher rpm ranges, you will experince lower milage.

The auto did the shifting for you so it would try to shift to the next highest gear when it "thought" it should. As you are well aware, that takes alot of the fun out of the driving experince. But, maybe you could drive a little more conservitavly for a while to see if your milage improves.

Sorry for the mispellings.
Rob

 

I've *never* seen mileage that low, even when traveling through Nevada in a manner than cannot be mentioned on CF. Something ain't right.

 

If you have a screwdriver and mediocre skills, remove your air cleaner and maf. Buy MAF CLEANER SPRAY (not electrical cleaner or anything else) and spray the hell outta your MAF, esp those little wires in there. Then inspect and replace your air filter as necessary. Replace with a K&N filter if possible. Sounds like you have a dirty maf and its throwing everything outta wack. A clogged/bad O2 sensor will do that too, are you throwing any codes? Drive around at high rpm for a while (5 mins or so) and see if the heat will clean the sensor out at all.

 

I wouldn't trust the car on this one. Try calculating MPGs yourself and see what you get.

98 M6 Avg. around 19 MPG

I have an extremely heavy foot.

 

Look at your average speed.
I drive mine every day, some in traffic and some around a loop at 55-60 MPH, but I was surprised to find that my average was only around 30 MPH. 15 MPG may not be too bad if you are only averaging 30 MPH instead of highway speed.

 

You should get better gas mileage than that with the manual tranny. You should be getting around 18-20 mpg in town.

 

the computer can be way off , it will vary so much that it has to be wrong.I have an 04 M6 ,my average is always around 17 and thats mostly city but I dont drive in a way to get good MPGs

 

Thanks for the responses. The 15 mpg is the "average" as per the fuel display and I've checked it against the actual gas mileage at my last fill up. The 15 mpg per the computer is very close to the actual mileage. I just wanted to make that clear. I would describe the driving as mixed -some suburban type driving and some highway driving. Also, I don't know if the engine is showing any codes, I guess I'd have to go to the local dealer or repair place to find that out. There are no mods on the car that I'm aware of.

 

Check this out on "how to get codes"
https://www.corvetteforum.com/techti...D=26&TopicID=1