Hey all,

I have a 2002 SS Camaro with bolt ons (Headers ,Exhaust, Intake, etc) that I recently moved from Denver,CO to Tulsa, OK with. That being said I have lost a bunch of MPG since move. I have also gained quite a bit of power from leaving 6300FT at my old home.

The car in CO would get 24-27 City in Denver with moderate driving. The last couple tanks I have gotten 16-18 and that is totally babying it. I literally probably am not seeing 2.5K on the tach except if I need to pass etc. I dont have a check engine light etc though its just getting bad gas mileage.

I tried cleaning the air filter and also the Maf with Maf cleaner and used some top end cleaner for the motor and saw maybe 2Mpg better but its just been horrendous I have been riding my motorcycle to save money on gas.

Car has 40K on it and 23K on this motor. Where should I start looking? I am using 91 Octane gas. It does smell slightly rich but it has always been that way and I dont see alot of soot etc on the pipes like its crazy rich but the MPG is a mess. It does idle a little rough. The RPM needle is rock solid but it lopes a little at idle, nothing major.

Thanks for any help!

 

I used to have an '08 Mustang that was like that. Anything below about 4,500' ASL and I'd lose about 12-15mpg on a steady highway cruise.

 

You said it yourself. Going from that high elevation to a low one gained a bunch of power but that doesn't come free. More power means less fuel economy.

There is alot more oxygen in the air down there and that requires more fuel. Nothing you can do about that.

 

get the car retuned .

 

I understand that I will lose some due to the power/alt. But does 16 MPG seem right on an LS1 at sea level?

I guess I will try and find a tuner here in OK.

 

I had a Saturn SL2 that got something like 55mpg in Colorado. Just a side effect of the altitude. I average 21-23 with mostly highway driving at sea level in mine. Oh and don't baby it, every time I do that to mine, my MPG goes down to 19....

 

not quite...my 99 sees 16-17 MPG city/hwy mixed driving... full bolton, H/C with 4.10s gears...I think the re-tune suggestion will put you on the right track...

 

Just a suggestion, but you might try unplugging your negative battery cable for 30 minutes and then reinstall to reset. This way the computer will relearn the new altitude change. It's free to do and may make a difference. If that doesn't do it you may look at a new tune but you will typically get better MPG at higher altitude due to the thinner air and not being able to make as much power. When I lived in Oklahoma 16-18 was about average for city driving in my stalled Trans Am.

Lonnie

 

If you're running closed loop then the O2 sensors will still desire to maintain stoich ratio... more oxygen, more fuel. I'm about 80' above sea level and when I had a stock LS1 I could still get around 30MPG highway; I seem to think my city MPG was in the upper teens.

 

For all the people blindly recommending a tune...if his car was perfectly tuned before and he's running both a MAF and O2 sensors then what is a tune going to do for him in terms of gas mileage?

 

Had to quote for the saturn rep. I have had a 1994 sl2 5spd for years at 560ft above sea lvl and see 31mpg beating on it and 33mpg babying it. stunning, and a newer 01 sc2 I got 38mpg thru the hills of PA cruise set to 67mph...

On topic though, in mixed driving my 00 ta m6 with bolt on mods in sig, achieved a max of 27mpg straight highway in ohio cruise @70mph. And fluctuates 17-20mpg in my mixed driving loop to work. So I see no issue with 18mpg in mixed w/boltons.