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Idle Problem when cold

Rockhound

Rockhound

New member
Have a 1995 Grand Prix GTP 3.4 DOHC and when I first start the car when it's cold outside the motor will pulsate to 2500rpm and then go down to around 500rpm then go back up to 2500 rpm's until it's warmed up then it runs and idle's fine. Any idea on what it could be that is causing that :th_scratchhead:. Check engine comes on when it's at low idle ,, and almost ready to stall then goes up again . Give it gas and the light goes off. A friend of mine is going to check the code next weekend when he is in town but trying to see what you guys think it may be . With the car warmed up I unplugged the MAF while running and the idle went up and plugged it back and idle went back down, so i'm thinking thats ok. Could it be the IAC? I unplugged the IAC while running and no change in the idle.

Thanks
 
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Rockhound said:
Have a 1995 Grand Prix GTP 3.4 DOHC and when I first start the car when it's cold outside the motor will pulsate to 2500rpm and then go down to around 500rpm then go back up to 2500 rpm's until it's warmed up then it runs and idle's fine. Any idea on what it could be that is causing that :th_scratchhead:. Check engine comes on when it's at low idle ,, and almost ready to stall then goes up again . Give it gas and the light goes off. A friend of mine is going to check the code next weekend when he is in town but trying to see what you guys think it may be . With the car warmed up I unplugged the MAF while running and the idle went up and plugged it back and idle went back down, so i'm thinking thats ok. Could it be the IAC? I unplugged the IAC while running and no change in the idle.

Thanks
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Well just to let anyone who is interested in this problem,, it was the LIM gasket and had them replaced ( upper & lower )problem solved!!!!!!! runs and idles great
 
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1995GrandPrixGTP said:
I am having the same problem, however, was this a costly repair?
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a little had a mechanic do it for me for around $900.00 also had another mechanic give me a quote of $1300.00 ,so check around. My daughter is friends with the mechanics daughter . I had upper and lower gaskets replaced plus my brake booster hose replaced also because when you hit the brakes hard the peddle would not go down for about 2 seconds because the hose would collapse being soft and that works great now. Cheaper to do yourself but it was money well spent for me as the car only has 73,000 miles on it Hope this helps :)
 
I think you both are getting quotes on the wrong engine. on the Lq1 the lower intake gaskets are very simple and do not require an oil change as no oil flows thru the lower intake manifold as in the 3100 and 3800 engines. if it is a 95 DOHC you will need: egr gasket, upper intake gasket, and lower intake gasket. Its prob a good idea to replace the spark plugs and pcv while it all was apart. also the common leak of the distributor o ring seal. Just lift that up clean it and JB weld it back shut. but for the issue in question the lower gaskets aren't more the 50 and upper is prob 20 and egr maybe 10.
 


Gotta love shops raping you for working on the Lq1. Ask your shop how much they would charge to change the alternator once. Bricks will be ****.
And I am sorry to say this but OP you got raped.
 
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