Hi. I pulled the IAC out of my 1999 GC 4.0, and sprayed it with brake cleaned and scrubbed the crud off of it. I kinda rushed through it because I was pressed for time. I also cleaned the passage that is goes in on the throttle body. I am still having problems with it idling. I was wondering if I should have worked the plunger in and out or not, or if it's just beyond cleaning.

 

Brake Cleaner, hmm? What did you use to wipe or scrub inside the bore? You really need to use Throttle Body Cleaner and a soft cloth or wood-handled soft bristled brush to clean the throttle bore, the underside and edges of the throttle-blade, the IAC and its bore, etc. And no, you should not physically manipulate the "pintle" of your IAC when cleaning but you can verify IAC actuation/function on the bench using ~4.5Vdc (three D-cell batteries plus a low value resistor or flashlight bulb in-series). It might be broken but you can prove it if you take your time...

 

Brake cleaner worked great. Got it nice and clean, scrubbed with a toothbrush and rag. Cleaned the bore and the throttle body. Jeep runs and idles perfect now. I didn't force the pintle at all.