I have a 1989 Chevy 1500, V8, 5.0, Automatic, about 160,000 miles.

It idles really rough at the start and sometimes will not stay running. I have to give her gas to keep her going. Once I get it started, the idles stay rough, from high to super low, for about 3-5 minutes. Once it settles the idle stays pretty low. A couple of days here and there it idles REALLY high. It goes through these 2 stages every so often but for the most part just the low idle and rough start. I have heard it could be many things from fuel pump to sensors. Just looking for some additional help from guys that know their stuff

 

I'm not an expert, but I had the same problem in a '93 S10 Blazer. It was the electronic EGR valve. Swapped it out with a new one and it was fixed. Although I think my check engine light was coming on with this problem. Just a thought.

 

Thanks! Any info is good info! The check engine light is coming on. I left that part out. The light flashes according to the idle. When it gets low the light comes on. Then sometimes it comes on and just stays on.

 

A dirty MAF can cause some nasty idling. Try reading the code when the check engine light is on. That would help narrow it down.