I was wondering why my gas mileage is Still bad. Replaced O2 sensor (april), coil, cap, rotor, plugs (all in oct), and wires (about a year old). Is it because we get a different kinda gas than the rest of the country???? Or is it because I do a lot of city driving? I last got 154 miles on a tank, and then filled it up w/ 11.9 gallons.

 

i get over 300 per tank and thats city driving highway i get over 30 miles per gallon with 202000 miles on the enigne

 

almost 13mpg.. do u do mostly city driving.. brake on.. gas on floor.. brake on?? that would explain ur horible gass milage (i cant really critize ppl that do that, cuz i do it too).. do have an exhaust leak somewhere? that would effect ur milage and performance..

something ive noticed thats helped me in all the cars ive had, run one tank of higher octane gass a month (87 normally, 91 once a month).. its helped me w/ milage in the past..

is cali the only place that has 87, 88.5 (most places around here still label this 89) and 91 octane gas?


-mike (loomdog)

 

after looking at what you've done, def replace the fuel filter if you haven't already. i replace mine, which seemed to be the original, and the gas that was left behind was disgusting.

right now i have MSD 8.5mm wires and the GM balster coil. and after replacing the fuel filter, cap, rotor, ignition module, and o2 sensor (all in trying to troubleshoot a hestation problem) , my gas milage shot up from 125 a tank to 225 a tank city....and 290ish highway.

 

Oh yea, but the fuel filter is about a year old, and it doesn't even have 10,000 miles on it. So I don't think it would be that.

Yea it's all city driving, once in awhile, I'll take the freeway, only on the weekends though. I usually just put it in Drive, because I never drive faster than 45 mph, and isn't that where it shifts to 4th gear anyway? Once I get on the freeway, I put it in OD. I just wish the mileage would be better, I mean, we do have the smaller engines of the F-Body (excluding 4cyl)

 

My car is running rich and I still haven't found out why....anyway:

100% City driving--- about 210-220 miles
100% Highway----about 320-350 miles
50/50 driving-----about 250 miles

The city driving is with a heavy foot though. The heavy foot has gotten me into a bit of trouble in the last 3 weeks so I expect my mileage to go up due to me switching to "granny mode".

 

When I first got the car it would do about 350 on highway and about 290-320 in the city. Though, my car has been running rich lately. Though, I do know why. There is a one way check valve that is connected to the air injection by-pass valve. If you dont know what that is it is the part that send Oxygen to the cat and O2 sensor. Well, at least that is how it was explained to me. When the one way check valve goes bad it send hot exhaust through it and burns the bypass valve. SInce the bypass valve is about $150 at the auto parts store and over $200 from the dealer, I havent been able to get a new one yet. So if your car is running rich that could be one of the problems. One way to know is that you will hear a very annoying exhaust noise from under the hood. Well, hope this helps someone.

~Josh~

 

back in the states I would get 300 miles a tank (not running on fumes in the E either), and that was city and highway combined. Over here I get 250 miles, but I'm also driving either city, hilly areas, or hauling @$$ on the autobahn, which is also hilly.

I just can't win

Maybe when I get done with the tuneup it'll get better. I hope

 

Gas mileage? What's that? I fill my tank every 3 or 4 days for local driving, if that helps... maybe 30 miles/day?

 

infinate mpg in the bird so far

But it has got to be better than the blazer or bonnie around town. The Blazer gets about 15-17 city, yuck. The bonnie, guestameteing less than that. no trip odometer.
Highway milage is better. The blazer gets, on a light load to K-Town, 330 miles on 1 tank(20 gals) of gas going average speed of 69 (shawing). The bonnie, when I drove from Minot, ND to K-Town, TN, driving average speed of 65, up to 450 miles a tank (26 gals) 17 mpg, but still about 8 hrs between fill ups. Both of those highway mpg are sad, so I'm hoping the bird will be a nice step up.

 

My records are:

-On Celebrity 2.8 V6 with 97 octane gas:
City: 17 mpg
Highway: 30 mpg

-On Corsica 2.8 V6 with 93 octane gas:
City: 17 mpg
HIghway: 25 mpg.

The difference: I think Celebrity has MAF and MAP (SD).
Corsica only MAP (without MAF).

Regards,

Denis V.