Try cleaning the IAC and it's port.
The computer is supposed to bump up the idle slightly when the a/c kicks on, to compensate for the additional load. It could be that the IAC plunger/bore have some build up in them and the IAC is hanging up and not allowing the idle to bump up.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.