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RPM drops on take off


jakeller10
09-14-2010, 09:35 PM
Hello this is my first post on the forum. I havea 2000 Grand Prix GT 4 door sedan. I have come here a couple times to diagnosis my problems. First problem I had was my car would die then I would restart and it would die. Happened twice. So I found out it could be the fuel pump. Change pump. Wrong. So I changed the fuel filter. Still no fix. It finally threw a code. Took to autozone and the reader said it was a P0102. Ahhh ha there we go. Changed the MAF sensor. Problem fixed. Not a chance. When car is cold it will start and run fine. When I stop after the car runs for a bit it wont start. It will fire up and the RPM's will drop and die. I have to hold down the accelerator for it to run. After a minute I can finally go. Then the other day I was driving and when I would stop at a stop light or stop sign, I would take off and the RPM's will drop. The car wont die just drop. The car idles at around 500-600. There are no new codes thrown. This is making it hard cuz if there was a code at least I can find out. I am thinking the TPS but if someone can direct me in the right way I would greatly appreciate it. Hope this is enough info. If not please ask away and I will try my best to describe.

BNaylor
09-15-2010, 11:45 AM
Try cleaning the ldle air controller and throttle body including the maf screen.

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rkvons
09-15-2010, 12:40 PM
Sounds like leaky injectors. You can put a fuel pressure gauge on it, start it up and note the fuel pressure, then shut it off and see if it drops quickly.

richtazz
09-15-2010, 02:47 PM
you didn't happen to buy a Cardone (or Auto-Zone Duralast) branded MAF did you? If so, unplug it and see if it runs better. If so, you got a bad one, like many who buy them as they are JUNK!

tblake
09-15-2010, 08:30 PM
I was going to suggest unplugging the replacement, but Rich beat me to the punch.

jakeller10
09-16-2010, 06:07 AM
I actually ordered it off ebay. From AIP parts. It doesnt say it is a Cardone. It said brand new OEM MAF. I paid $124 for it. So the symptoms I described doesn't lean towards the TPS? I appreciate the tips. What do I use to clean the IAC and throttle body with? I am new at trying to fix things like this. The parts in the throttle body seem easy to fix just gotta find what is causing the car to run like crap. Like I said it runs great cold but once it warms up it wont start unless I keep the foot on the gas and also when I stop at stop signs or lights it hesitates really bad at take off.

jakeller10
09-16-2010, 06:08 AM
Also when I put the fuel pressure test on after I got the new fuel pump in it was reading around 40-42 psi. Is that normal or should it be higher. If it is a leaky fuel injector what do those run or is there a way to fix it? Thanks once again for all the help guys.

BNaylor
09-16-2010, 10:22 AM
For cleaning use throttle body cleaner. Stp or crc brand. Fp is low but not abnormal. Test at fuel pump prime. Engine off ignition to on only. 46 psi for na sii 3800 engine.
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