My brother dropped his 1998 F150 with 4.6 in my driveway after the engine took a dump while pulling his camper. Apparently all was well until he stomped on the throttle and the engine lost all power. The plugs and wires have been replaced with OEM Ford parts, I've checked the coil packs, and replaced one of them, and shifted the one I took off to the drivers side bank with no luck. I've checked the injectors, they work. I've checked the wiring to the injectors, that's all ok. I checked the fuel pressure, and that's ok, and yet this engine runs like crap. it misfires, has no power, and shakes pretty bad at idle. There are no stored codes in the ECM. I even drove the truck for 30 minutes with it barely running and still no check engine light, no codes, no nothing. This engine has over 123K on it, and I'm beginning towards the possibility that the chains were loose enough for the engine to jump time.

I see several other posters have had same/simular issues but have yet to find any cures for this truck.

Any help much appreciated! Thanks!

 

Do a compression test.

 

subscribing

 

Check for vacuum leaks, also.

 

first vote on blown head gaskets... or the PCM is shot. those would be my guesses.

 

clogged cats ?

 

Is the timing cover emitting a bad sound? With no codes your problem is mechanical in nature. Backfiring? With no misfire codes? So your Air/fuel is messed up. Yet you get no rich or lean codes. Look for bad headgaskets.