I've recently replaced the timing chains on my sons 04 F-150 5.4. Now I'm getting a code PO174. I've changed 2 coil packs, fuel filter, MAF sensor and cleaned all the connections. Fuel filter had what looked like brown fuel coming out of the in line of the filter. I'm stressed out now, the truck does not even have enough power to drive up the driveway. Backfires, spits and sputters, has rough idle.

 

Sounds like it's out of time. Did you replace the phasers also, and did you use the proper timing marks for each side, L/R, with the crank keyway at 12 0'clock?

 

Yes, replaced all components and checked it twice. The code is PO 174 I just checked and cleaned the oxygen sensors. OS 1bank 1 and 2 before warm up data stream is .010 to .775 after normal operating temperature reached OS 1and 2 bank 1 and 2 going crazy.

 

If an engine is backfiring, its most likely a timing issue.

If the engine wasn't backfiring before the timing chain swap, then most likely you need to go back over the chain alignment procedure carefully.

 

Before the chains and guides were replaced it was running rough, no power and giving codes for both camshaft senors. Changed both sensors and crank sensors. Now bank 2 lean. I'm re checking time and changing plugs tomorrow.