hello I have a 2008 f150 with the 5.4 triton 3valve and had a lot of issues with it in the short time I had it, I have just replaced all coils and plugs, one converter, anyways it cleared up my jerking when it kicked in to over drive and the miss it had but I still have a stumble in it when its at an idle and when I go out and shove it to the floor it doesn't have the power it should its like something is holding it back then lets it go and so on so if someone could please help e out with this problem it would be great! Because my mechanic just shakes his head and tells e he don't know...So any help would be greatly appreciated !!

 

Also when it does this sometimes you hear what sounds like a backfire with in the exhaust it sounds like??

 

Nothing???

 

Sounds like a cat issue. Any codes?

 

Not sure but I was thinking cat issue too but everyone else seems to have same issues but not so simple fixes, maybe I'll just guy the cats