I have read many threads but hear it goes 2006 5.4 3v flex fuel if it matters replaced all plugs @ 60000 and all cop s @ 62000 but it still has a skip or miss @ wot or when pulling a load and under acceleration usually above 70mph cleaned mas and have done all maintaince as per ford fuel filter ect any help or point me to the thread i need to read runs good all other times and has allways gotten crappy gas milage its A 4x4 with 33s

 

Take it to the dealer and tell them you want to have a compression test done . I did and found out that I had 10% compression loss in two cylinders. They are taking the engine apart as I type this...under warranty. 57k miles on it.