A/C on idle issue
 

on hot days ive had the AC full on, this at stop lights has had the jeep idling poorly. it runs like its stuttering at 600ish rpm.
IAC is stock but recently cleaned a few months back with the TB, no other running idling issues outside of 3-4
AC on.

what the heck can causes this?

Did you also clean the throttle body?

Yes

What year?

99 auto

Cleaning of the idle air control CAN, but does not guarantee full function. There are electronics in it and if and when those fail, cleaning won't be the fix.

I'd recommend replacing it. With a MOPAR IAC from your Jeep dealer.