I have a 2002 gtp...for the past several months ive been having all kind of problems with it.Thought it was transmission at first i was experiencing hard shifting so i had epc solenoid replaced,didnt fix it.well i continued getting hard shifts and throttle position sensor codes (replaced sensor 3 times).I kept driving with hard shifts and slippage until finally trans gave up and died.I got a low mileage used tranny and replaced all shift solenoids,tcc solenoid and epc solenoids before i had it installed.So i pick my car up today after getting the used trans installed thinking my problem was fixed.Car drove great until it got to operating temperature then the hard shifts started again.The rpms bounce up and down at low rpms when driving.if i get on gas at WOT it goes away for a lil while then comes back.If i turn car off and let sit for awhile it drives fine again until it gets warm again.im at a loss for cause...MAF,IAC,EGR or any other sensor...i have cleaned MAF and throttle body last month so i dunno what to do next.someone help me!!!


edit:i doubt it has any significance but my trac light stays off and abs light is on also

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2002 silvermist GTP...a few mods

In my monte carlo I had the trans rebuilt. When the car got up to operating temp it would buck when slowing down or taking off from a light. It even stalled out a couple of times when I was slowing down. I took it back to the trans shop and he had to either replace or adjust the TCC switch. Basically his excuse was, "we can't always get 'em right the first time." After that I never had a problem with it, but it kinda reminds me of your problem. Just because the part is new, does not mean that it is garunteed to work right.

Also, the rpm's bouncing up and down make me think of the IAC being bad. That is always something else to look into.

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'02 Galaxy Silver GTX Coupe. SLP Headers, SLP cat-back exhaust, SLP 1.8 RR, ZZP 3.4/3.25" MPS, SLP hood, SLP CAI, Overkill PCM, 180 t-stat, SSIC, S1 TB, AL 104's, F/R STB's, F-body calipers.

well i cleaned MAF and throttle body again and cleaned IAC.As soon as i got to cruising speed the RPM's started jumping and down....so i put the car in third kept steady at 3000 rpm's no rpm's jumping...got down on throttle til i hit somewhere over 100 mph shifted to drive and let off gas...bam! throttle position sensor code again...trans still shifting hard into every gear when drving normally...shifts fine when i go WOT.So basically its only gettin jumpy rpms at 2000 or lower.also my boost indicator light stopped working around the time all this started happening.

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2002 silvermist GTP...a few mods

i could easily be wrong but i would place a bet that it is your fule pump belive it or not.

i thought about that at work today...which would explain why it only does it hot...car ran great today kinda ,drove over 100 miles...for a few miles it felt like i lost power...so i guess ill get a new fuel pump and see what happens.

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2002 silvermist GTP...a few mods

fuel pressure is good...got some more codes today...now its sayin p0101 MAF/VAF along with the throttle position sensor code i have been getting for 3 months now...i thoroughtly cleaned MAF the other night...i notice when i get on the gas i get an unburned fuel,exhaust smell in the car.And a really rich exhaust smell from car when its idling...any ideas?

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2002 silvermist GTP...a few mods

Pressure is one thing...volume quite another. I would check the fuel pressure regulator.

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One Big Ass Mistake America

thanks... ill see whats up with that

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2002 silvermist GTP...a few mods

Your best bet would be to get a technician with a GM Tech II scanner and monitor the transmission parameters when it warms up and starts shifting improperly. You can also double check all the readings from the engine sensors at the same time. Otherwise you are just shooting in the dark and wasting money... Hope it works out for you!

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Thanks
Scott McKinney
http://www.motortopia.com/cars/16218" onclick="window.open(this.href);return false;

your trans might be going into hot mode. Could be a type of short. Im not great at solving tranny problems though.

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1999 Pontiac Grand Prix
303HP/353TQ
Mods: L67 swap w/3.25" pulley,PRJ LL cam, speed daddy headers
2008 BMW 335i TT-jb4 tune.BMS intake.AA bOV and charge pipe

i got it fixed after hours of trouble shooting...the vac line that goes into intake under the S/C snout was disconnected causing the throttle position sensor code to be tripped...thus causing the trans slippage and late shifts.runs great now...thanks for all the input.

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2002 silvermist GTP...a few mods