'92 F150 kicking and bucking
Working on my '92 F150 with the 4.9L engine and have been getting an occasional miss in the motor. Not sure if it is fuel or spark related, but when it happens the truck starts jerking and kicking and bucking. Seem to do it mainly when the engine is under a load, like going up long hills. It has never stalled yet and I just can't figure out what is causing it. It runs fine around town under light throttle and never misses. I checked the codes and everything passes.
I have changed the following parts trying to fix this issue, but nothing has made a difference yet:
Fuel pressure regulator
Spark plug wires
Cap and rotor
Distributor coil pick-up
I have checked the fuel pressure and it tests fine. I have dual fuel tanks and the problem happens on either tank, so I know it isn't a pump problem. I am at a loss for what is causing this and tired of throwing parts at it in the hopes of fixing it. Figured I would check here for any suggestions before I bite the bullet and take it to a dealer for diagnosis.
Was thinking maybe clogged injectors, but then wouldn't it run bad all the time? Was also thinking maybe a plugged cat convertor, but when on flat ground I can mat the gas pedal and it speeds up just fine with no missing.
Without any codes from the computer, I don't have a clue on what to test next. Open to any and all suggestions.
1964 Galaxie 500XL, 352cid, Cruise-o-matic, 9in rear, white w/white interior, all original american iron as it came from the factory.
1992 F150, 4.9L, E4OD, 8.8in rear, red w/gray interior