Thought I would post a FIXED thread to hopefully help others. I spent hours combing threads trying to find an answer to my idle issues and found a lot of useful information and a lot of posts with the originator never saying if / how they got their problem fixed.

Mine turned out to be a MAF relay.

This was on my wife's 1987 IROC with 5.7 TPI (L98). Over the course of last year it gradually developed an idle issue and intermittent code 34. It would idle too low and sometimes stall, and other times it would idle unusually high (above 1,000 rpm). The problem would strike at random and then go away for weeks. The idle issue became so erratic that it even caused shift issues with the transmission because of the high/low idle while coasting. It began to get worse this year and progressed to the point it would die frequently at idle and I had an almost constant code 34 (MAF). There were no other codes. I refused to believe it was actually the MAF itself. In the process of diagnosing I discovered some bare MAF wires possibly grounding out on the water pump near the MAF connector. Fixed those and the problem was gone briefly, but eventually returned. Still refusing to accept it was the MAF itself I searched a LOT of threads and eventually decided to replace the MAF relay, even though some of the trouble shooting indicated it was the MAF. I didn't bother to test the relay itself because it appeared 1987 original and had been opened/re-sealed with RTV at some point, and I don't mind just replacing old factory parts that are suspect.

Standard Motor Products # RY31. $21.99 at O'Reilly's. This is the MAF relay, not the burnoff relay.

I replaced the relay, cleared the trouble codes, and the idle problem instantly went away and the trouble code has not returned. Here are a few links I found especially helpful.

https://www.thirdgen.org/forums/tech...ck-my-maf.html

https://www.thirdgen.org/forums/tech...or-relays.html

https://www.thirdgen.org/forums/tech...ff-thread.html