99 Venture, high idle

I have a 1999 Chevrolet Venture LS van that has an intermittant high idle problem on start up. When I notice the problem shutting the car off and re-starting it usually clears the problem. I have heard this may be a vacuum leak(?) but I think it may be electronic like a throttle position sensor going bad. Any thoughts? I want to avoid a shop bill if I can manage this repair at home. Thanks!

One thing that can cause a high idle is a defective Idle Air Control valve.

Locate the IAC valve on the throttle body. And the next time the idle goes out of control, take the handle of a screwdriver and rap on the IAC valve. If the idle changes when doing this, replace the IAC valve.