I am have problems with my 2007 f150 5.4 triton with 106k I am 80% positive it's a misfire issue from all the symptoms I'm seeing however I can't seem to eliminate it. The symptoms are, I can accelerate up to 40-45 it will sometimes start to hesitate and start shaking and the check engine light started flashing like a misfire, when you hook it up to a scanner it throws a misfire code first one was cylinder 8 I replaced all the coils and plugs it drove fine for about 15 miles started hesitating again so I checked codes again pops up as cylinder 5 now but it's not a hard code so it'll disappear and can't seem to get it back. Also my o2 sensor is bad now which from what I have found online is an indicator of a misfire. The plugs when I pulled them needed to be changed I don't know when they were changed last I just bought the truck at 105k on it and had the exhaust manifold gaskets replaced along with the studs for them the the 4wd wasnt working and had that fixed also.

I have been told to change everything from the fuel filter, the coils again, and even have the pcm updated.
Does anyone have any suggestions on what could be going on? And possibly how to fix it?

Any help would be greatly appreciated.

-Austin

 

1. Post ALL the actual codes
2. What plugs were used?
3.. What COPs were used?
4. Were new boots and springs used, WITH proper application of dielectric grease?
5. Check yer FPDM: https://www.f150online.com/forums/ar...placement.html
6. Replace BOTH front O2's (80K maintenance item)
7. Check injectors fer leakage.
8. Other maintenance - clean yer MAF & TB. Replace the fuel filter - it's a yearly maint item anyway.

good luck