Trouble shoot, Chevy Truck

My 94 Cheyenne W/T 4.3 has problems with surging when im at a redlight or I turn the truck on and leave it in park or neutral until it eventually turns off. I can put it in drive and it will drive fine but it likes to surge and almost shake when I stop at red lights. Not entirely certain what do replace next. I replaced the O2 sensor, replaced the fuel pump and filter, within the past 2 years replaced the distributor cap wires and plugs and am definitely in need to do that again but I cant figure out what might cause this. Maybe it’s out of time and I need to replace the whole distributor rotar? Maybe the EGR Valve or the idle air control? What do yall think

The problem might be the Idle Air Control valve hunting for the proper idle position.


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My fiance works for Orilleys so I get a good discount but we are on a limited budget. Think it would be acceptable to clean the old IAC with carb cleaner to see if that helps? I’ve heard it doesnt help but if I can save money it’s much preferred

Cleaning only works if the vehicle stalls because the IAC valve/throttle body is dirty.

When the IAC valve hunts for the proper idle position, it usually means the IAC valve is defective.


Well I guess its worth a try then. Worst case I have to go use her discount. Thank you very much, hopefully it is just the IAC

I don’t remember the specifics, but I seem to remember a lot of drivability issues on these trucks being a faulty coolant temperature sensor. You might try and disconnect it and see if the issue goes away.