Check the spark plugs and the injectors...the 04-05 have injector issues.

Mine had the #7 injector stick open and numerous others on the boards have had the same issue...if ran for awhile with it stuck open you can hydrolock the motor or blow out the cats and 02 sensors.

The plugs can break on you (millions of threads on this) and should have been changed by now.

Other than that I love my 05 5.4....I bought mine with 38K miles and now has 80K....its had its issues though (flex plate, starter grind, injector failure, warped front calipers, bad TPS sensor) Other than that just normal maintenance

 

i definately love my truck n i dont have anything bad to say about it or about ford. **** just wears out, i was just sayin the situation really sucked

 

I have 122,700 on my 2005. It has been meticulously maintained both by me and at the dealer. I have all the records. I have had a tuner on it for 91,000 of those miles. The truck has been driven fast at times on the highway but never abused. I posted this week that it had used 1/2 qt of oil in 4500 miles. I would not hesitate to pay $9,000 for a truck like mine.