88 rough surging idle

2.9L MPI - Will die on cold start unless you bump the gas for a few seconds and keep the idle up around 2K. Later, will often surge and a stop, or just idle rough.
Replaced plugs (suspect), wires, IAC valve, checked intake for leaks. I suspect the plugs because I bought these fancy platinum no-gap plugs. I think I changed too much at once. Ideas?

Welcome to AF, general symptoms, but this is a 2.8 Chevy correct? Check for fuel pressure at the rail, also major vacuum leaks. Check for both injector fuses being good also.

I know this post is 4 years old, but did you figure the problem out?

If you have the same issue be sure to look at the egr also, that was common for not seating causing stalls and hesitation. with the 2.8.

Thanks for the suggestion. The EGR was relitively clean, and I cleaned the IAC valve as well. The problem remained..BUT, I obtained a shop manual and I figured it out.
It seems that the power steering pressure has a lot to do with the idle control when the engine is at operating temp. I found leaking and cracked power steering hoses, as well as power steering pump seals. I replaced them all, and my surging idle issue is gone.
My Cimarron is an '86, lets see if these new hoses and seals last another 26 years.