Fast Idle Problem
Thread Starter
Burning Brakes
Joined: Apr 2008
Posts: 1,190
Likes: 68
From: Woodland Hills California
Fast Idle Problem
2008 Z51 with Vararam intake and Powerwedge.
I had a P0121 CEL code show up. I took the throttle body off and cleaned it. I also cleaned the MAF sensor. Put things back together and started driving the car. Idles at 1200 to 1400 rpms until I completely stop, then goes down to normal 600. I tried disconnecting the battery and driving for about 120 miles, no change. I then tried the idle relearn procedure - run for 2.5 minutes with coolant temp starting below 120, turn on a/c and other electronics to load engine, then shut down for 1 minute, lastly repeat. Still fast idling.
I have read about using a GM tool to reset idle. Does this do something different than disconnecting battery?
How can I tell if the throttle body needs to be replaced?
In addition, the Vararam has been on the car for almost four years and did not cause a fast idle problem. I installed the Powerwedge about 2000 miles ago and did not have a idle problem The fast idle started after removing the throttle body and cleaning it. So the car has idled properly with the Vararam and Powerwedge installed.
I had a P0121 CEL code show up. I took the throttle body off and cleaned it. I also cleaned the MAF sensor. Put things back together and started driving the car. Idles at 1200 to 1400 rpms until I completely stop, then goes down to normal 600. I tried disconnecting the battery and driving for about 120 miles, no change. I then tried the idle relearn procedure - run for 2.5 minutes with coolant temp starting below 120, turn on a/c and other electronics to load engine, then shut down for 1 minute, lastly repeat. Still fast idling.
I have read about using a GM tool to reset idle. Does this do something different than disconnecting battery?
How can I tell if the throttle body needs to be replaced?
In addition, the Vararam has been on the car for almost four years and did not cause a fast idle problem. I installed the Powerwedge about 2000 miles ago and did not have a idle problem The fast idle started after removing the throttle body and cleaning it. So the car has idled properly with the Vararam and Powerwedge installed.
