2002 Grand Prix high idle

shumway
Posts: 4
Joined: Wed Feb 27, 2013 4:05 pm

2002 Grand Prix high idle

Unread post by shumway » Wed Feb 27, 2013 4:09 pm

I have a 3.1 that will start normally, but then after a while the idle jumps up to 3-4k when it's usually about 1. It goes down when I shift it into gear, but it's still high for normal. When I put it in neutral or park, the idle jumps way back up again. Sometimes it does it, but not all the time. I've cleaned the MAF & changed the throttle sensor, but I still have the same problem. Any clues?

User avatar
ProTech
Posts: 651
Joined: Wed Oct 17, 2012 10:08 am

Re: 2002 Grand Prix high idle

Unread post by ProTech » Thu Feb 28, 2013 9:13 pm

You might want to recheck the throttle position sensor, as your description is exactly what happens when you have a faulty sensor. If you installed an aftermarket sensor, you might want to try a GM part. You can tell if the sensor is bad by trying to turn the inner portion that attaches to the throttle body with your finger. It should spring back into position. Normally, when the sensor is faulty, you can just keep turning the middle of the sensor and there is no spring action to it. This will cause the idle issues you are experiencing.

If that still isn't the problem, you're going to have to start checking for vacuum leaks, EGR problems, debris in the intake path, etc....and other things that can cause a problem like you're having.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

shumway
Posts: 4
Joined: Wed Feb 27, 2013 4:05 pm

Re: 2002 Grand Prix high idle

Unread post by shumway » Sun Mar 10, 2013 9:27 pm

Checked the sensor & it springs back like it should. If it starts idling high I can unplug it then it idles normal.

User avatar
ProTech
Posts: 651
Joined: Wed Oct 17, 2012 10:08 am

Re: 2002 Grand Prix high idle

Unread post by ProTech » Sun Mar 10, 2013 9:29 pm

You might want to try a different throttle position sensor. If you can unplug it and it idles fine, then the problem has to lie in that area.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

shumway
Posts: 4
Joined: Wed Feb 27, 2013 4:05 pm

Re: 2002 Grand Prix high idle

Unread post by shumway » Wed Mar 27, 2013 5:22 pm

It's been a little over a week since I installed the new sensor. So far, so good.

Thanks a bunch!

Post Reply

  • Similar Topics
    Replies
    Views
    Last post