I'll check it out, but I'm sure it has nothing to do with the stop screw.

 

Cruiser has a great point, if you disconnected it, it will be a whole lot easier to feel which side is hanging up. (bracket/TB, or cable /petal).

Here in the pic where you can see bare cable is where that little crumbling black tube was. Idk if that could keep it from coming to the stop or not. Mine was trashed though.

After you pop the socket off the ball below, you need to press in at least one of the keepers there on the cable housing end to get to come up out of there. They are front and back. When I had that end free I raised it up the end so oil would run down, left it like that a while.

Also of course you can check the petal and it's pivot as well. On other cars, not the Jeep, I've seen that rot and get sticky.

 

If the stop screw were backed out too far, the butterfly can be wearing into the bore of the throttle body.

 

But his high idle? Does sound like it's not "making it home". Maybe, once again I'll learn something new here. "well don, the iac bone is connected to the...

 

It's more from the "leaving no stone unturned" form of diagnostics.
If it were me, I would disconnect both the TV cable and accelerator cables and see what the TB does. If it's still sticky, the tB needs to come off for further inspecton. Anyways, 600 RPM is too low of an idle.

 

Got ya'. So if it will go to 600, it might be because someone "fixed" the adjustment, (or bent it). I might have accepted that on a manual before..

Anyway, another good point on that trany kick-down cable. There's an easy fix! I just push the button down and set it with a little clearance. I really don't know it it's right, but SEEMS OK. Nothing on mine seems to "auto ratchet"or anything.

The trany kick-down is never gonna hold the idle up.