RrCoX22

iTrader: (6)

So my vehicle it seems has been having some issues with getting mileage out of the tank since I purchased it back in October.

Last tank after filling full I got about 175 miles out of it, which seems to be pretty below average.

Now I have driven about 25 miles over the course of a few days of highway and city mixed on a new full fillup. My fuel gauge level is about on the 3/4 tank full mark.

So you would assume that the car has a fuel leak. I've checked underneath from the fuel rails back to the tank and nothing is leaking. The car has about 42,000 miles and so far I have cleaned the air filter, replaced the fuel filter, seafoamed the fuel tank, sprayed the MAF, checked tire psi, and looked for vacuum leaks.

My next step would be replacing the plugs and having the injectors checked. Otherwise I would assume maybe an injector is stuck open or there's a tunning issue that needs to be dealt with? The car doesn't smell like it's burning rich. Kind of at a loss at the moment. Ideas?

Starz T/A 17

iTrader: (6)

It could be the plugs , also how long are your average trips with the car? If you make a ton of short trips without allowing the car to reach operating temperatures it could drastically hurt your fuel millage b/c engines only operate at maximum efficiency when its within its designed operating temperature.

RrCoX22

iTrader: (6)

ya... by the time I reach work it's about getting up to full operating temperature and out of open loop. this is about 1 mile of street driving and 2 miles of highway driving

Z28-4Ever

iTrader: (4)

yea i got the same problem going on i get 175-180 miles on a tank driving normal. and i checked same stuff u did and no problems. need to know gas is killing me lol

gold98Z28

iTrader: (7)

do you do the math by how many gallons vs. miles you drive to see actuall MPG or just going off the gauge? could just be a faulty or bent sending unit from having the pump changed... you never said acutal mpg so thats y im tossing this out there

gold98Z28

iTrader: (7)

its all that corn they are putting in our gas now adays. you cant find 100% gas anymore. pretty soon we are all gonna be alky's. lol

NastyNate65

You can make some good power on Ethanol. Our motors just dont like it. So im not at alcoholic

itsslow98

iTrader: (18)

yea fill it all the way up, drive it till you use a almost a whole tank(go by gauge) and refill it all the way.....divide the mileage by the gallons u use to fill it back up. then let us know what the mpg is.

RrCoX22

iTrader: (6)

ok well I forgot to mention ya... I kept track of my MPG last tank by tracking the odometer and trip at the same time to make sure there was no difference.

I got 178 miles out of my last tank and put about 12.9 gallons in it which is about 13.8 MPG

Doing the same this tank and also using this site here to double check: http://www.mpgtune.com/index.php

Sommer86

iTrader: (46)

I have a mini stalled A4 (2400). LT's, pulley, ls6 intake. I used to get about 220-230 miles per tank and if I work the nozzel, I can get 16.9 gallons in it.

I just tuned (by "12secss" - George Lara) my rich running car (that didn't smell rich, but my rear bumper showed it) and now on my 2nd tank I'm averaging 270 a tank. That's 40-50 mile per tank difference. I'm loving it now. Too bad I didn't do the tune 2 years ago.

Edit: Oh yeah, and i've got 3.73's out back too!

RPM WS6

iTrader: (3)

That's some shitty mileage, especially for an M6 car.

I just did 17mpg, mostly city driving with several short trips. That's an A4 car with 96k miles on the stock plugs too. I usually get as high as 24-26 with mixed city and highway. I've never done straight highway though.

I would say you have an issue somewhere.

boostednismo

iTrader: (5)

Also check your O2 sensors, they may need replacing. Is the car throwing any codes?

RrCoX22

iTrader: (6)

no codes being thrown... don't know if O2 sensors would be it either with only 40k miles, but have heard of them starting to go bad without even throwing codes

it is pissing me off since it's drinking fuel pretty bad

samson_420

iTrader: (1)

That sucks. . . . I say it should be above 20, at least.


The only thing I can think of is to check all your basic crap. Fuel filter, air filter, plugs, make sure it's not throwing codes(I know you said you already did). . . . .


I don't know where else to look. . . . .


You could also check your compression. . . . I just don't know where else to look.

ds98formula

iTrader: (3)

So that a total of 3 miles to work. Thats a pretty short trip. I get great milage if i drive over 15 miles but when i do a lot of short trips it eats it fast. Try taking a road trip some where and see what you can get out of the first quarter of a tank to make sure its not just the short trips killing you. All highway I have been able to get 90-100 miles out of first quarter. Fuel consumpsion problems suck. Good luck

P.S O2 will not throw a code until they are very bad so it could be slow switching but just above the amount need to keep the code from being thrown. If you have access to a scan tool you can look at them and see how fast they are switching.

BobDoLe

iTrader: (11)

RPM WS6

iTrader: (3)

With my old commute, it would be like clockwork, first 1/4 tank would always get me exactly 115 miles. That was with 75% highway and 25% city on that route.

I hear about lots of M6 guys doing 29+ MPG with pure highway driving. I beleive that, seeing as my A4 has done mid-20s with some city mixed in.

Z28_LT1

iTrader: (2)

I get about 230 per tank. thats with a 50 mile daily commute, mostly freeway... wish I could get 270 though...

AR15 guy

iTrader: (1)

Something isn't right. I average about 210 miles per tank (18.5mpg) with a stock A4 Formula. I would expect a m6 to do better than that. Check the basics first and see whats going on.

How do some of you get 16+ gallons in your tank? Everything I have read says I should have a 16.8 gallon tank, but even if I let it go to E and the light comes on I can barely get 12.5 gallons in mine. Either I have a 4 gallon reserve or a 13 gallon tank like my LT1 had.

Z28_LT1

iTrader: (2)

I don't think the LT1 had a 13 gallon tank. i think it was like 15.5 or something...