Thread: Idle issue

Alright, so I have a 2001 grand prix GTP and at the moment it is having problems idleing. The problem started on the first rainy day I drove it in since the new engine was put in about 5k miles ago. While I was driving It all of a sudden the RPMs started jumping 1000+- while I was going down the road. The gas pedal didnt really make a differnece. Made it to work miraculously and then it wouldn't start from their. I tested for air leaks and replaced the supercharger intercooler gaskets and also replace the MAF IAC and TPS. Just replaced the spark plugs with autolights 104 gapped at .060. The plugs that I took out had oil on them and were black so hopefully it's not a bad piston ring. The engine is completely modified and was built from ZZPerformance and haven't had any major issues till now. My battery isnt the greatest but starts everytime. At this point im about out of ideas so any ideas or suggestions are much appreciated. If a list of mods will help just ask and I'll post them. Currently running a 3.0 SC pulley, I even tried starting the car without the SC belt on and it did the same thing. I posted a video of it trying to start on YouTube so I'll post a link for that in the next post

Link for the video - 2001 Pontiac Grand Prix GTP Idle Issue - YouTube

Damn. Didn't even think about that. Probably about a month ago or so I replaced the Crank Sensor. I'll take a look into it

i wont be able to take a look at the car for a few hours so does any one have anyone other ideas so that i can check it all at once

Well, good idea but no go. Checked it out and it did have a little bit of moisture on it but cleaned it and the sensor and plug in with the same results
Any other ideas?

Originally Posted by tcman49

some grand prixs have speed throttle issues

The Throttle Position Sensor should control the "speed throttle" which I replaced, also the idle air control valve and the mass air flow sensor are all brand new.

Im having similar issues with my 01 GTP. Just going down the road with my foot off the gas the throttle has a mind of its own. When i put it in park the rpms usually shoot way up... weirdest thing! Brought it into the mechanic today who cleaned out the throttle body. Now it idles where it should at about 900rpm instead of 1200rpm like it used to but that didn't fix the problem. Did you ever find a solution? My mechanic said its probably the tps or iac.