kowalenko93
New Member
I recently bought a 2002 z71 Tahoe with the 5.3 and 215k miles and noticed when it was cold out the idle would fluctuate. it would drop down to 300 then bounce back to 1000. It continues to do this even when its warmed up until its turned off and then started again.
I thought it might be the IAC valve and dirty throttle body. I removed the throttle body and it was very dirty and cleaned it and the problem continued. So I ordered a new IAC and installed it. the idle still fluctuates and now when I start it the idle shoots up the 1500-2000 rpm for a few seconds and then goes back down. And when I shift into gear the rpms go back to 1100 and it tries to take off on its one and will get up to 20mph. But if I hold down on the brake when I first shift for about 10 seconds the rpms will lower and it wont do it.
I got it checked for codes and all it came up with was knock sensor.
I don't know if it matters but when I installed the new IAC valve I forgot to disconnect the battery.
Any ideas?
I thought it might be the IAC valve and dirty throttle body. I removed the throttle body and it was very dirty and cleaned it and the problem continued. So I ordered a new IAC and installed it. the idle still fluctuates and now when I start it the idle shoots up the 1500-2000 rpm for a few seconds and then goes back down. And when I shift into gear the rpms go back to 1100 and it tries to take off on its one and will get up to 20mph. But if I hold down on the brake when I first shift for about 10 seconds the rpms will lower and it wont do it.
I got it checked for codes and all it came up with was knock sensor.
I don't know if it matters but when I installed the new IAC valve I forgot to disconnect the battery.
Any ideas?
