I know it sounds strange. I recently picked up an 82 Trans Am. Lg4 auto. Only 50,000 original miles and appears very well kept up. When I start the engine cold, the idle remains low, around 600, and the engine shuts down unless I rev it for a while. However, later when the engine is warm the idle, in park, is high, around 1200. At times, it diesels when I shut it off, from the high idle. Where should I start? I do know the choke does not close when the engine is cold, but, here in Vegas it's 100 degrees, so I don't think that is an issue. Thoughts?

 

The choke also operates the high idle cam, so it is important to get the choke operating.

 

Thanks Vader. My choke now works and the car starts up fine. The check engine light occasionally comes on, usually when the engine is warm and I am stopped. It turns out to be a code 45. The car drives well. One thing I did notice is the MC solenoid does not click when I turn the key. Maybe that is throwing the code.