Hey Guys,
2002 Grand Prix GT
3.8 173k
I am having an idle issue with my grand prix and I have searched the forums but still cannot find a solution. I know this is long, but it’s the only way I can explain it. Please bear with me. Attached is a video of what it is doing. FYI in the video, it was me that was revving it up when it went to like 4000.
So my grand prix is idling all over the place. It will surge from 700 rpms to 1500 rpms and even die sometimes. If you rev it up, its crisp. The night before this happened, I drove it 60 miles and when I parked it, it ran great. The next day I went to go start it, and it ran fine while I let it warm up for a few minutes, then I went to take off and it died. I then could barely make it a block with the pedal half way to the floor. I pulled it over and put it in park and it was revving up all over the place. Just idling from 700 rpms and then itd jump up to 1500-1800 all by itself and just keep doing that.
I put some heat in the fuel because I thought maybe water was in the gas. I let it sit and run for a few minutes and then decided to try it again. I drove it 30 miles and as long as you didn’t let it idle it seemed to be fine for the most part. Then it got worse.
The next day I went out to work on it and now it wouldn’t even staying running. You had to hold your foot on the gas to keep it above idle and then it ran fine. If you let your foot off the gas, it would go under 1000 rpms and then die.
This is a list of the things I have replaced/tried. FYI the intake and gaskets were changed 20,000 miles ago.
Replaced MAF sensor (Two of them)
Replaced MAP sensor
Replaced Idle Air Control Valve
Cleaned throttle body
Sprayed carb n choke cleaner around the intake to see if it changed.
I put a scanner on it and it read codes for the bad MAF and MAP sensor but I think that was because I unplugged the MAF sensor to see if the idle issue still existed. After replacing both, there is no code for the MAF or MAP.
Then a week goes by with it just sitting, and the battery died. So I charged the battery and started it and the idle issue was gone. Weird huh.
Then I went to drive it back home and I was filling it with gas and it started doing it again, but then stopped and it was fine while I drove it 30 miles. I’m sure it is going to come back but I don’t know what else to do here. The car has plenty of power and doesn't miss a beat if you floor it. It's only an idling issue.
Another random thing that started to happen was the onstar randomly would come on while you were driving, so I pulled the fuse.
I am just at a loss.
Thanks in advance.
Dereck
