1988 GMC won't idle

Check for vacuum leaks.

First thing pull the TBI unit and check the gasket under it as I had one go bad on me a few years back and do the same thing.

"SnoMan" wrote: > [quote:fe71f4c5da="quark1150"]Hey Guys > I'm hoping someone here has some info on this EXTREMELY > frustrating problem. > I have an '88 GMC Sierra p/u 5.7 liter, Turbo 400. For a while > now it will > not idle properly. It simple dies unless I keep my foot on the > gas. I have > checked the plug wires, changed the plugs , dist, and rotor, > changed the MAP > sensor(diagnostic code was set), checked the IAC valve and > coolant sensor > according to the Haynes manual, changed the fuel filter and > air filter, and > run countless quarts of fuel system cleaner through it. I can > hear the fuel > pump running when I turn on the key. Most of the time it runs > fine while > driving, but occasionally it seems to have a miss and lack of > power at lower > RPM's. The engine and trans were rebuilt about 22,000 mi. ago. > Does anybody > know what this could be? Have I missed something simple that I > should have > checked? Any help is appreciated. Thanks![/quote:fe71f4c5da] > > First thing pull the TBI unit and check the gasket under it as > I had one go bad on me a few years back and do the same thing.

Check the EGR to see its not clogged with something.