11mpg on fox w/ only bolt ons???

[madonionrs]

I have a 89Covt AOD. 89,000miles 125 miles to the tank????
Mods: 3.73(same with 2.73) exaust work...
Seems to be running good, although I'm kinda a car n00b in experience sector.

I don't smell gas anywhere and I had the car dynoed and the curve was pretty smooth except for a slight dip at 1-3k

 

[Black Sun 5.0]

Give it a full tune-up and replace the O2's. Maybe run diags. It's a start. I have a similar issue, but not as bad as yours.

 

[madonionrs]

Give it a full tune-up and replace the O2's. Maybe run diags. It's a start. I have a similar issue, but not as bad as yours.

Yeah... I put in some autolite 24s, fuel filter, k&n, cap&roder and bought a new iab (bad idle)

I'll have to replace the O2s.... You think they would make that much of a difference

 

[StreetStang37]

you should be able to get atleast 15-16. I get 20-22 mpg on the freeway and 12.5-15 on the street and thats with just about all the bolt ons you can get + heads + cam and gears.

 

[johnt785]

Try filling up your tank twice and doing the math over again. You know just to make sure the 11 mpg was the correct out come.

 

[madonionrs]

you should be able to get atleast 15-16. I get 20-22 mpg on the freeway and 12.5-15 on the street and thats with just about all the bolt ons you can get + heads + cam and gears.

Lol, I don't have any engine work done and my VERY BEST street mpg was 16.9 w/2.73s. Now my best is 130m or 140miles to the tank (which is what.. 13mpg?)

 

[SuperStang83]

When my 87' was stock I got 23 around town and 30mpg on the highway!

Jakob

 

[Silentst2000]

When my 87' was stock I got 23 around town and 30mpg on the highway!

Jakob

That's better than my 94 v6 can do...

 

[Cue-Ball]

Both of my cars have stock engines. No real mods other than cat-back exhaust. For my daily use i only get about 14-15 mpg from each of them (one auto, one stick). Driving around town is just killer on gas mileage. I've gotten 25mpg before with my auto on the highway. Never really taken the manual car on a long trip to determine highway mileage, but i'm guessing 22mpg would be the best i could expect.

When you got your car dynod, did you have an EGA hooked up? If not, that's something you can try that would be pretty inexpensive ($50 or so for a dyno run with EGA). That should tell you if you're running rich or not. If you ARE, then you can start diagnosing. Maybe your O2 sensors need replaced or maybe you're stuck in closed loop mode. If the EGA comes out at around 12:1 or so, then you just have to accept that you're not driving a fuel efficient car.

 

[madonionrs]

When I had my car dynoed they didn't use a EGA. I went their on their Autumn festival ($25 pulls)
A full dyno is like $89 here in Buffalo

 

[Mustang5L5]

I only get 150 miles per tank with my car.

But i blame it on the way i drive.

 

[Black Sun 5.0]

What would cause a car to get stuck in closed loop and how could you tell? It's a shame how so many people on this board seem to have incurable gas mileage problems for no good reason at all and despite the combinaton of both time and money, the problem never gets resolved. Or, at least rarely.

 

[bmo37]

before my heavy mods my stang got 10-12mpg total lucky to get 200miles (usually160-180) out of a full tank. I only had, full exhaust and intake, puleys, maf, put new o2's tune up, everything but couldn't solve the problem stang still gets the same milage now with the engine stroked go figure

 

[Black Sun 5.0]

I used to get 27 hwy, 20-22 city. I'm now down to 14 MPG EVERYWHERE. The elusiveness of this problem is frustrating. Where's Ford when you need them?