1998 Cherokee 4.0l runs fine then about a minute idles rough, and when you floor it, it clears up. What would cause this issue?

 

Check air idle control valve on the throttle body.

 

I have had two causes for a rough warm idle.
1. Used autolite plugs one time. Chased a warm rough idle for a few weeks until I went back to champion coppers. Problem went away.

2. A couple years later, it was back. I had replaced the coil awhile back with an echlin form NAPA (was chasing a different problem). Went back to a MOPAR cold and warm idle problem went away.

In both cases, it seemed to run fine, except at warm idle.

Definitely worth checking/cleaning the IAC too. those cna get pretty nasty. It can be difficult to get a socket in there. When I do anything on the throttle body now, I just take the whole throttle body off. Take the air intake tube off (flat blade screwdriver). 4 bolts holding it in, couple fo electric connectors and done. then you can clean the whole throttle body too. If it's never been done, it can use it.