My '87 Suburban, 5.7L, started acting strange recently. Upon cold start-up, it idles very low and I have to keep the accelerator depressed to keep it from stalling until it warms up. I suspect the idle air control valve on the TBI unit but I'm not sure.
A week ago I had some welding done on the muffler and I'm not sure if there is any connection there, i.e. voltage spike or something. Oddly the truck wouldn't start after the muffler work and the problem determined to be a poor ground to the fuel pump. It ran fine for a week then became hard to start. I bought the truck new and have never had a problem on start-up.
My repair shop reset the ECM and performed the case learn procedure but I"m really having trouble with cold winter starts. Any thoughts? Thanks..