Very low mpg's...

[GoHard]

I am seriously tapped out. I can't figure out what the problem is. I consistently get 14mpg in the city. and that is with me driving like ms.daisy, never wot, never bogging it, and shifting at 2k. My car is a 02 ws6 m6 it has 25k miles with these mods:

Slp lid, paper filter
Ported stock TB w/coolant bypass
160 thermostat
Crank pulley, alternator pulley
ARH Offroad headers, ARH catted Y
!AIR
Slp loudmouth 2
UMI: adj. panhard bar, lower control arms + relocation brackets
BMR boxed weld-in subframe connectors
MGW shifter
Dyno tuned

I have done every maintenance there is to be done. New spark plugs, wires, air filter, fuel filter, new 02 sensors, and cleaned MAF. I can't call it. I really hope someone can help me figure this out.

[Fbomb]

put a 195 tstat back in, reset fans, then see what happens. I gained like 2mpg going back from 160 to the stocker. 160 has absolutely no benefit anyhow unless you advance timing.

[1BADAIR]

long idle times from city.
nothing you can do about MPG if your not moving

[98blackbeauty]

I usually get average of 15.7 MPG in city urban driving. I don't drive hard shift usually 2000 2500. MPG is a lot of where your driving aswell as how you drive. Very little slow city driving mostly 5-6 lights and 50 miles and hour.
What gear do you have mine is 3.42

[Fbomb]

I usually get average of 15.7 MPG in city urban driving. I don't drive hard shift usually 2000 2500. MPG is a lot of where your driving aswell as how you drive. Very little slow city driving mostly 5-6 lights and 50 miles and hour.
What gear do you have mine is 3.42

Makes me feel better about my car...I get like 16-17 city but I have a 3.23

[farmington]

I have a 99 A4 z28 and with 3.73's and a 2800 stall converter I got 18.5 in the city with my last tank. Got 20 before the gears and converter, but I think I'm getting into the throttle a lot more now because its a lot more FUN!

[Fbomb]

Oh yeah, might help to mention it's a H/C/I Formy.

[GoHard]

I'm on stock gears as well...

[LS1_Sean]

Thats strange. I got 17mpg driving normaly but at nights WOT freeway runs and races.
But i usually get 20mpg in urban city driving. Change the stat and talk to ur tuner about doing some road tuning.
WOT tuning is different that crusing rpms

[Fbomb]

Hey, check for exhaust leaks at the header flange to head. Mine developed a pretty massive leak and I got a quarter tank to 12 miles yesterday...I need to sniff my oil before I start it again. O2's read lean and the computer's like "oh, hey, let's add fuel!"

[GoHard]

I had someone listen to that "hissing" noise when under 2k rpm and he said it just sounds like headers and not an exhaust leak, I doubt there is any exhaust leaks. Could the powerstat really do that much damage to the mpg's?

[SSTODD]

I would question the "tune" and not the stat. so much. What about dragging brakes or other issues? It is a modded V8 and we are not usually looking at mpg's.

[GoHard]

I would question the "tune" and not the stat. so much. What about dragging brakes or other issues? It is a modded V8 and we are not usually looking at mpg's.

I had my tuner go over the fuel trim a couple times and even he just doesn't know why I'm getting the low mileage. I think I need to plan a nice long trip and see what I get on the highway.

Dragging brakes? What else could it be you think?

[Fbomb]

Well I just modified my tune a bit and got some AWESOME gas mileage on the way up to school for what my car is. Gauge moved about as much as when the car was bolt-ons. Still have to fill it to see what I got but I was getting ~30 hwy.

[ICEPICK]

200 miles or less highway on my car. 15 glln tnk, its just a mild tune.