I know it is an F150 forum, but my 06 Explorer with 4.6 3 valve has basically same motor as the 5.4 3v.

My EB has 198k miles, and has been so far very good to me, but now I am facing some major issue with the engine.
It makes a bad noise when hot, and in gear. Not sure if I need new engine or rebuild the timing components or something else.

I welcome any experts to listen to those and share your thoughts:
In gear:


In Park

 

That does sound pretty bad. I have heard similar noises on 5.4 3V engines before as well. I'm not exactly sure, but that sounds like a VCT issue. The fact that it does it when it's hot kind of tells the story. Your oil pressure might be dropping too low at hot idle to properly adjust the cam timing, causing the knock. And also when you rev the engine up, it quietens down. I would look into checking the oil pressure first with a gauge tapped in at the oil pressure sending unit port and seeing what it's reading hot and in drive - at idle. Specification is 25 PSI at hot idle, in drive.