What is your oil pressure at hot idle?
Noises in the valve cover (s) can be, but are not restricted to; collapsed lifter(s), bent push rod(s), rocker(s) that are loose/worn/broken. broken valve spring(s) or bent push rod(s). Then there is the possibility of a bad cam lobe(s).
Merry freakin Xmas......
"Taking care of our veterans is a cost of war. If you can spend six trillion dollars sending people to war, you can spend a few billion dollars taking care of them when they come home"
Sen. Bernie Sanders (I-Vt.)
If what doesn't kill you, makes you stronger, I should be able to bench press a Grand Cherokee by now!