Thread: Crap gas mileage?

I have an 04 gtp and ever since i got the car i have had horid gas mileage compared to my 2000. I have gone threw the car completely. Changed plugs, wires, fuel filter, air filter, mobil 1 oil/filter, blower oil, cleaned tb, maf pcv. Ive put a intake on it and headers with egr and cat delete.
I know the egr wont help but it shouldn,t make my gas mileage go from 30-35 mpg i got on the highway with my 2000 to 17-19 i get babying the thing with my 04. Anyone have any ideas?

Originally Posted by Kolton Lock

Get it tuned for reduced performance? I don't know why it would be that bad..

Are your brakes like pressing on the rotor all the time?
Like the pads. Obviously you'll press the brakes every once in awhile lol

dont think so ill jack it up and check anyway

i dont want reduced performance and i shouldnt have to do that there is obviously something else wrong here
ive even seafoamed it and run in injector cleaner through it a couple times

Any check engine lights?

Originally Posted by Fivefingerdeathpunch

Any check engine lights?

no besides the obvious egr and for some reason there was non for 300 miles after the cat delete but there may be now, but no there was no codes befor the egr and cat delete

Originally Posted by SJAndrew

Vacuum leaks?

and not that im aware of



Im goign to take the injectors off and give them a real cleaning

I only got around 20mpg in city around 25hwy. That 180 Tstat probably isn't helping you either I would go back to stock tstat. Are tire pressure correct? How many miles on the car?

Having no cat or EGR and not being tuned for it, is my guess on why your mpgs suck.

Originally Posted by Fivefingerdeathpunch

Having no cat or EGR and not being tuned for it, is my guess on why your mpgs suck.

ya but it was just as bad befor

I cleaned the injectors, car is running better than ever but i think the only way im going to figure this out is hooking it up to a computer cus i have no idea what was done to this thing befor and there is 91k on it

I get like 16 or 17 city and 28 highway in my 99 gtp.

Originally Posted by Erik Adam Rodriguez

15 mpg city and 20 highway its just something you expect with more power. try taking off the intake and putting stock back on, cause with more air flowing the pcm is adding more fuel

Intake increases fuel mileage because it takes less throttle to achieve the same speed.