2002 Express 3500 Van High Idle

[TimiN467]

Once engine starts it will rev at 3500 rpm and will not come down. There is no documentation on how to adjust idle can anyone help me? This is so frustrating.

[Bob86ZZ4]

Tim, there is no idle adjustment per-se on this van. The computer controls everything. Now, if you have a high idle there are two things I would look for. An air leak around the throttle body/intake manifold can do it. Or, a sticky idle air control motor (commonly refered to as IAC). The IAC screws into the side of the throttle body and has an electrical connection to it. I would do some internet searching for IAC and your van to see if you can find a diagram showing exactly where it is. I don't know for sure on your engine. Usually it is very close to the butterfly valve in the entrance to the throttle body. Take the rubber air intake boot off and look around that area. If you find it go ahead and unscrew it and inspect the tip. If there is any crud on it clean it off with throttle body cleaner. And spray a bunch of it in where you unscrewed the IAC also. The seat that the tip sits into could be clogged up.

Air leaks around this area can sometimes be heard if they are big enough. If you're idling at 3500 rpm's you might have a big leak. Take a can of brake or throttle body cleaner and spray it around the throttle body base and intake mating areas while the engine is running. If there is a leak it will suck in the spray and slow down the engine momentarily.

Good luck. Hope this is some help.