02 gt poor fuel economy [Archive] - GrandAmGT.com Forum


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12-02-2011, 06:23 PM
hello, i own a 2002 ga gt. bought the car with 170000 and a bad motor, bought jasper motor and trans out of a freinds junkyard, paperwork included, had roughly 10000 miles on it. tree fell on car, thats why it was there.

anyways, have the car for about 9 months, originally got around 22mpg combined, then was averageing around 18 now im down in the 15 range. Its also gutless, came from driving a 4cyl saturn and at this point that car would run circles around this one.

not a dash light on in the car, so no obvious leads. was considering replacing the cat but for the price of one I really dont want to start just throwing money at the car. Not afraid to spend it if needed, but also dont want to throw 200$+ if it needs a cheap fix.

any ideas would be great!

12-02-2011, 11:20 PM
when mine began doing that same thing my cat was getting clogged. Was the previous motor burning anything? Coolant and cats dont get alone well. its like a cat (as in meow) and water. they dont mix.

Soon you will start hearing a strange sound, followed by a louder strange sound. i never once threw a code for it either.

12-03-2011, 11:37 AM
not rally sure what was going on with the last motor, i dont remember any noticeable smoke from the exhaust, but i do remember it had bearing noise. started and ran enough to get on and off rollback, thats about all i can tell ya.

and what kind of noise are u refering to?

12-03-2011, 12:59 PM
i didnt notice any kind of smoke either. but when i had my LIM go i know i had a bunch burn. Replaced it then. Then i had a head gasket go. Had to replace it again shortly after that.

The noise sounds like its just under a constant load. Then you begin to hear it from under the car. Almost a rattle. Once it gets bad enough you wont have the power to get it up a hill hardly and the noise will be loud. Shortly after that it will start backfiring.

The good news is that its not a super expensive fix. but its also not the cheapest thing you can replace. See if you can do some kind of test somewhere to make sure its flowing properly.

12-03-2011, 03:26 PM
ive already priced out a cat, my thing is if im going to replace the cat id probably do the whole exhaust, thats why im just poking around to see if theres anything else to look for before i dump 500$ in it and not have it fix the problem. thanks for the imput tho. i live in a rather hilly area and im gonna take the car for a ride just to see if i hear anything out of the ordinary

01-17-2012, 07:06 PM
so as an update, ive replaced cat, new plugs wires etc. and still 13.5 mpg average. im at about my wits end with the thing. a freind suggested taking it to the dealership and having them take a look at it. i say no engine light so things cant be out of value that far. Im begining to think that the motors just a dud. Any thoughts?

01-17-2012, 09:49 PM
Take it to advance auto and see if it has history codes and Have you changed the IAC and the TPS. And when you replaced the Cat did you replace the O2 sensor ? Fuel filter clogged will cause bad fuel economy. And may I ask , where is coal township ?

01-17-2012, 11:30 PM
no i have not changed the iac or tps. nor did i change any O2 sensor while i changed the cat, fuel filter replaced at time of cat...roughly 2 weeks ago. i dint know advanced would have the scanner to tell history, i dont think that the autozone i go to has that type of scan tool. and as far as coal twp, about halfway between harrisburg and williamsport in PA

01-18-2012, 04:53 AM
its worth a try or if you have a friend at a dealer or carlot that has a tech2 they could tell you whats up And i thought that town sounded familiar been thru there on the railroad a few times good luck and i hope you get things straightened out !!!