Rough idle, fouling up plugs after rebuild
We just rebuilt a 1991 Ford E150 (302 5.0L) with EFI.
We followed the rebuild procedure to spec, replaced the crank, crank barrings (which came with the re-manufactured crank), cam, lifters, oil pump, water pump, distributor cap and router. radiator and switched out to an electronic fan with thermostat. we also lightly tapped the valves with compound making sure not to take too much off.
Problem. When the engine idle kicks down the idle is VERY rough and it will eventually sputter and die. after about 1hour of run we pulled the plugs and the plugs are fouled up with black deposits. Also the exhaust smells very rich but no smoke.
Checking for Codes it does throw a 33 which seems to point to an issue with the EGR valve. I think this might be it and plan to check it but wondering if you folks can consult me if you think this could cause these symptoms and if there is anything else I can check?