There's no easy way to test the automatic idle speed motor. It's bolted to the side of the throttle body and has four wires in its connector. There's four coils of wire in it. Testing with an ohm meter won't work because if one coil is open, the meter will just read through the other three coils.
You can unbolt it, pull really really hard to pull the pintle valve out, then watch if it moves when the ignition switch is turned on, but that doesn't mean much either. Be sure the torx bit fits snugly in the screw heads. Those screws have Lok Tite on the threads so the screw slots round out easily.
Mechanics check the operation with a scanner. I use Chrysler's DRB3 scanner. That lets you select any idle speed up to 2000 rpm in 200 rpm increments. That motor has so much control that it can keep a V-8 engine running with 6 disabled cylinders. Obviously it won't run smoothly, but it will run.
Here's a photo from rockauto. Com to show what it looks like. This is for a 5.2L I wasn't aware it is different for a 4.0L but all I can see different is the orientation of the connector.
Thursday, February 23rd, 2012 AT 9:47 PM