1995 Chevy C10 1500 5.7 350 engine
183,000 miles. Surges and sputters when accelerating at low speeds, 20 -35 mph, runs rough as if it is missing at low speeds.
1) Replaced the coolant temperature sensor
2) Replaced MAP sensor
3) Checked the throttle sensor response is as required
4) Checked the O2 sensor via propane torch test, checked fine
5) Replaced the Fuel Filter
6) Checked the EGR valve, seems fine, pushing up on it stalls the truck at idle so doesn't seem stuck.
7) There are no Check Engine Lights and no trouble codes via the paper clip method on the OBD1.
8) Rotor, plugs and wires are new as of 4 months ago.
Running out of all the basic things to check or replace. (It seems that if the O2 sensor where the issue it would not have these symptoms on startup when still in open loop, is that a correct assumption?)
This started suddenly as if something had a hard failure, prior it was running fine.