I have a 2007 f150 xl that had a 5.4 swap from an 03 expedition. I got the truck dirt cheap with lots of problems. This is the 3rd time it's sat for an extended period of time in 4 years. (Twice since I've owned it) my first time, I had a mobile mechanic do a throttle body cleaning and after the next fill-up it ran like crap. After weeks of replacing plugs, coils, and various other efforts I gave up. By chance I noticed that the passenger side exhaust was extremely hot and eventually I cut the cats off and *poof* problem solved after sitting nearly a year... for 6 months.
The last of those 6 months, I noticed the battery light occasionally coming on and it would either go off or stay off if I turned truck off and started again. One cold morning otw to work when the battery light came on while sitting at light. When the traffic light turned green I accelerated then punched it. When it shifted into second gear it stalled then caught, followed by a horrible knocking. I stopped at the next light to turn around and it died. I turned it off and tried to crank back up. It was hesitant but did, so I puttered back to the house and turned it off with the assumption I blew the motor. I added oil because it was very low and tried cranking it again hoping for the best, but no better.. Last week I needed to move it so I jumped the dead battery in an attempt to drive it up on a trailer. When it first cranked it knocked for a few seconds but nearly stopped entirely.
after reading countless forums... I am hopeful it doesn't need a new motor. The alternator is fairly new (less than a year) the belt is pretty old. The wiring is a little rigged. And the knock is coming from what sounds like top passenger (hard to tell with exhaust cut at cats)
Is it possible I didn't burn a bearing? Yes I know I abused the hell outta the truck

 

Disregard... I gave a Youtube video for the 3v 5.4. Misread post above.

 

Manual, that doesn't apply - the 5.4 in the 03 Expy is a 2 valve.

 

Oops, I misread it. Sorry!