Coulda knocked crap loose and stuck up a lifter? Maybe an exhaust leak? Mine did this for like a week after I got it and I was scared it was the bottom end, but it just randomly went away... haha I know that doesnt help, but its the same thing you described. Had a noise only at idle, sorta sounded like a knock or tick it was hard to tell, had a random rough idle. Replaced spark plugs, and switched oil filters (mopar) and the issue went away. Rough idle went away also with the filter brand change. My jeep really likes high milage semi synthetic. Be warned if you switch to that you may have to stay with it, and change the oil sooner because it cleans up gunk. But it has done good by my jeep so far, and zero oil leaks or seeping, and drastically helped my valve seal leaking/oil consumption. Anyways, get a stethescope on it, and see if it does it at idle vs revved. What is your oil pressure like?
Ps, u joints making it knock?
01 TJ, 32RH, 4.0, 8.8, hpd30, 35's, metalcloaks
07 CBR600RR, full Akra exhaust, PC V, etc.