You won't believe it! I have a 2004 F-150 5.4L Triton engine with ~ 71,500 miles (1800 miles over my extended warranty!). The engine light never came on but I was experiencing some power loss and shaking. The dealer went through process of elimination on the engine codes (not exactly sure how they determined what to fix since no light was on) which included the following repairs: new oxygen sensor; replace 2 cam phasers; and complete tune-up including DFI (???) to reduce possibility that the plugs would not be broken during the process (even with the $120 DFI, they still broke 1 plug which cost an additional $85 to remove). So after $2,300 I drove the car off the lot. The next day, I called the dealer and explained that I hear a constant engine ticking and was told that it is probably on the other side of engine and a "lifter" issue which is typical with this engine. He said that if he was me, he would simply use a heavier weight oil (10-30) and live with it.
So 300 miles later, the engine totally locked-up on me and had to be towed back to the dealer. The only thing the dealer has disclosed was that the engine coolant jug was empty and that it appears that the issue may be around plug #5. They need to pull the head and see if bent valve, etc , etc.
So I am kind of at the mercy of the dealer. Is this a coincidence or could they have messed something up during the $2,300 service such as the camshaft timing which could attribute to this? All I know at this point is it will take > 10 hours to diagnose the problem, and dealer mentioned it may be cheaper to buy a new engine than fix this one...they don't know yet! Can you believe it!
Any advice would be appreciated!!!!!

 

How does the service rep know it's going to take over 10 hours to diagnose the problem?
What is DFI? That's a new one on me. Also you said there was no CEL. Yet the dealer had engine codes to diagnose? I know I'm not being much help.

 

I think the rep was guessing the time it would take to pull the head? The "DFI" ( could have it wrong) was described as a procedure to reduce any excess carbon that is a common cause of breaking plugs...unfortunately it wasn't 100% effective. Where did the dealer get the checklist to begin fixing the problems - they told me they got the list of items to fix and priority sent to them directly by Ford???