'90 clbwgn loaded 302, when i start it from a cold start the eng nearly dies for a moment then comes up to it's normal hi-idle, then down to normal idle. At cold start,this summer if the a/c is turned on when i start the eng the idle hunts until i shut the a/c off. I'm open to suggestions!

 

Clean your fuel injectors, and throttle body. Then check your TPS sensor. It was giving me fits on my 93 F-150. It stopped...

 

You might try scrubbing the throttle plate bores with a nylon barrel brush,just like a shotgun barrel brush,and carb cleaner. Just open the plates wide open and get busy. No need to clean very far inside, just where the plates touch the bore when closed and a little past that.
Phillip

 

Also check for vacuum leaks around your manifold and your vacuum hoses.

Slik