Rough running after warmed up generally only at idle and starting off. Chevy 1500.
I know this is a long shot but the internet has held surprises in the past.
I have a 94, 305 two barrel throttle body, auto trans, 4X4 with 100K. From cold, starts and runs fine. After it warms up and waiting for a light to change it will run rough sometimes. Sometimes it can be "cleared" up by raising revs in neutral. Sometimes accelerating from stop in this condition it will "buck" possibly backfire before it returns to normal. Worst case has been after being warmed up and going through one of these episodes, parked truck while running fine and 15 minutes latter it would not start. It fired and "tried" to start but would not. Let it sit for 3 hours, started and ran fine all the way home and restarted fine after a 5 minute wait once home.
I am assuming it is not mechanical or plugs as latter are fairly new and when running fine it will pull smoothly and strong past 4000 RPM.
Guess would be some sensor but which one, or hopefully not ECU.
Any help / suggestions would be greatly appreciated.