I have a 2005 f150, 5.4L, my truck misfires at idle, at higher speeds she is mostly fine, some misfiring but not that bad and some when i accelerate but not that often. the misfire is enough to were it seems like it might be more than just one bad cylinder. im not showing any codes anymore, before it was misfire in cyl 1 but that was it. i have done and had the following done trying to fix the problem:

1. timing chain, tensioners and guides were replaced
2. plugs replaced, twice
3. coils replaced , first time replaced 4, all 8 second time(at dealerships recommedation)
4. cat converters replaced
5. O2 sensors replaced all four
6. knock sensors replaced
7. cam position sensors replaced
8. maf sensor replaced
9. cold air flow system installed
10. injectors cleaned at dealership
11. new fuel filter
12. seafoam treatment in tank and manifold, twice
13. compression test, normal

she has seen three mechanics and one dealership and still she misfires. i love my baby and i dont want to have to put her down so if anyone has any ideas please throw them my way as im willing to try anything at this point cause im at my wits end . I really appreciate any help i can get.

Gus

 

Is it triggering a CEL? If so what cylinders show a misfire? I would check for Vacuum leaks, I do not see that in the list of things you have there. Best way is with a smoke machine. ALSO look hard at the EGR system. Good luck

Frank

 

gonna give vacuum leaks a shot to see if anything comes up, thanks for the feedback

 

I had experienced once some misfire but on another car, turned out that the Maf sensors connector was broken from the inside.
you can give it a shot. Gluck