I've have a '15 model with a 5.0 it has 160k miles on it. When I first bought the truck with 80k miles on it I noticed a knocking sound from the engine on 2 seperate occasions. I turned the truck off and started it back and it went away both times. I put 80k miles on it and the knock never happened again until last week. Now the low oil pressure light is coming on and the knock is back.. I've cranked it a few times in the past few days and it's as quiet as can be then shows a low oil pressure light and starts knocking. I've changed the oil and it has plenty in it. Have never noticed metal in it and have only used synthetic oil and motocraft filters. It had the following codes show up. P0430, P0355, P0011, P0014, P0021.

 

You have three seperate problems indicated by the codes.
P 11, 14 and 21 all indicate both banks camshafts are over advanced.
P355 is cylinder 5 coil primary faulure >>a misfire.
P430 is a cat converter fail bank 2. Very likely the result of cylinder 5 missfire if you kept on driving the truck and allowing unburned gas (cylinder 5) to light off in that converter and melting the substrate..
Bottom line is you have some costly major repairs to have done.
I'm not suprised at the knocking you hear.
Good luck.

 

I haven't driven it since it started. I have cranked it in my driveway a few times. Sometimes it sounds normal for a minute then oil pressure bottoms out and it starts knocking. I've already bought a new motor for it but trying to figure out what could be wrong with the one that's in it.