Grand Prix idle/(cooling?) problems

[Andrew_W]

Hi, my name is Andrew and I have a 92 Pontiac Grand Prix SE 3.1L FI FWD V6. The car has just over 119,000 miles on it.

One of the main problems I have with the car that I haven't been able to fix is an idle problem. Namely when the car is at normal operating temperature (~180 degrees F). Whenever I'm at a light, the light turns green and about 80% of the time, I let off the brake and try to go to the gas, then the car dies. So I have to throw it in neutral and restart it. It also sputters sometimes while I am on the gas, and I can stay on the gas at the same position and it will eventually kick back up and accelerate like normal. I've scanned the car numerous times and the only code it showed was an "idle air problem", which I researched and found the problem was supposedly remedied by cleaning the throttle body and replacing the idle air control valve. Well, when I cleared the code, it didn't come back until a friend of mine was replacing a cooling hose for me, and he scanned it and found the same code, so apparently my fix didn't help it. I'm not sure what else an idle air problem could be but I have replaced numerous things before this including fuel filter, throttle position sensor, idle air control valve, and cleaned the throttle body.

My friend that replaced the cooling hose for me said that he noticed one of the two cooling fans were not kicking on and then the check engine light was coming on. He suggested I take a look at the cooling temperature switch which I researched and I believe it is located on the block right under the water outlet. I haven't taken it out to look at it, but since it's electrical, I figured either it's bad or it's not and the only way to know is to replace it, but I wanted a few more opinions before I did so. I was also wondering if the cooling fan relay would have anything to do with that problem?

Also, I went to check my spark plugs the other day and I could distinctly smell unburned gasoline on the three I took out of the front of the engine. I'm not sure if this has anything to do with the idle problem, but it seems like it could be.

Any information would be greatly appreciated as I need this car to last at least another 6 months before I can afford any type of loan or another vehicle.

Thanks again,

Andrew White

[Andrew_W]

bump

[richtazz]

The second aux fan will only come on if the AC is on, or coolant temp exceeds 240 degrees. Since you replaced the IAC, but the code is still there, I would inspect the harness that plugs into it. If that looks good, then I would suspect the new IAC is bad. If I had a nickel for every time I've heard "but I replaced the ______, that can't be the problem" I'd be typing this from my own island in the Carribbean.

[Andrew_W]

Well the second fan doesn't come on even with the A/C turned on. I didn't remember to put that in the first post; I knew I was forgeting something.

And where is the harness located?

[richtazz]

Just follow the wiring from the IAC as far as you can and see if you can see corrosion or a cut/rubbed spot. As far as no 2nd fan operation, check the relay in the underhood relay center for the aux fan.

[Andrew_W]

What is there to check for on the relay? I always believed there's no way to tell if they're bad except to replace it.

[richtazz]

swap it with the primary fan relay for testing purposes, they are the same part number.

[GDP2007]

I just brought a 2000 Pontiac Grand Prix SE V6-3.1L VIN J with 119+Kmiles. I took it to get a diagnostic check and the computer reads P04889-AV Vent Solenoid Control Circuit malfunction or something like that. Can you explains what that really means somebody? Is it anything I can do to fix it?

[richtazz]

Welcome to AF GDP2007. Since your question is unrelated to this thread's original subject, you may want to start your own thread so more people see your question. Plus, it's against AF guidelines to hijack someone elses thread.