Thread: 2002 grand prix running rough! (Please Help)

I have a 02 grand prix with the 3.1L and when i start the car it will try to stall out, if i give it a little gas it will balance out and run just fine for a few minutes. Then it will start to run rough again, Yesterday I opened the hood and was checking some things and while the car was running I unplugged the intake air temp sensor that plugs into the top of the intake elbow and when I unplug that the car runs perfect. I sat there and unplugged it and plugged it in and out like 50 times and everytime same thing it ran perfect when unplugged and like crap when plugged in. So I ran up to autozone and I bought a new one and came home and put it in. When I put the new one in the car did the same thing. It ran like crap with the new one plugged in and when I unhook it then it runs perfect. Its got me confused. Could autozone have sold me a bad sensor, or could there be something else that is causeing it to run rough like it is, and if thats the case then why does it run perfect when I unhook the sensor? By the way the service engine light is not on, there are no codes being thrown either. If anyone has any ideas I would really appreciate it. Thanks Alot Everyone

Just wanted to give an update I got in the car and went to drive it and it would start right up then stall out then it wouldnt start at all. I still had the intake air temp sensor out of the car since thats seemed to be what was causing it to run like crap but now im even more stumped since it started doing the same thing as before i pulled the sensor again. Please can someone help me out here, I have looked through a bunch of pages on here and i cant find a solution. I find people with similar problems but then when i read further into it they never turn out to be the same thing. So please anyone that has any ideas ive got the time and im willing to try anything as long as it makes sense and its not too extreme. thanks for your time everyone.

You need to pull any trouble codes that may be stored in the PCM. Now that you pulled the IAT sensor wire with the carr on, your sure to have the "check engine" or
"service engine" or whatever you want the call it, ON. If the light is not on, you might have a burned bulb, do you see the light on when you turn the ignition "ON" before you start the car? You stated that the light was not on in you fisrt post which will initially think me to believe possible bulb malfunction with the engine light.

Thanks Quicksilver I didnt even pay attention to that anytime I started the car, But I just ran outside and checked and the service engine light does not come on when you turn the key. So the bulb is burned out. Im gonna take the car up to Autozone in a little bit to have them put the scanner on it and see what codes come up cause im sure its gonna have some. Thanks again for the input I probly wouldnt have ever noticed the bulb was blown if you hadnt said something. I will post and let you know what codes show up after i get back from autozone.

Your welcome.
If you plan on working on your car yourself, and have others in the family with OBDII vehicals, you might just want to pick up a code scanner while at AZ.
I picked up a nice OBDII scanner at AZ so I could check the codes on my Grandma's Saturn (uses CAN network), It was on sale for $99, regular $129, and it covers all 96' and newer OBDII. The nice thing about it is that it not only reads and clears DTC's, it also will display real-time data from the sensors while one drives the vehical, and for $99, that's a pretty good deal. That way you have it with anywhere you are, and plug it in while driving down the road at anytime. No dealing with other people when you have just a little problem.

Yea thats a good idea, I didnt even think about that. I always figured the ones for around 100 bucks were cheap and probly didnt work all that good. Maybe I will just pick one up, I havnt had a chance to make it up there yet. I plan on going up there tomorrow. I will post what I figure out. Thanks again for the help.

New to this forum. I bought an 07 GP GXP a couple months ago and had a problem similar to this too. Would idle rough and accelerate rough. Except mine was (i found out) that one of my cylinders had a miss fire and the check engine light came on. I went to O'reighlys part store and used there code reader and erased the code and has been running with no problems since.