Interesting notes:

1. The bouncing idle is now more "Frequent" after I cleaned out the IACV and topped off the coolant. Before, it usually starts after a "long" drive, but now, it starts almost immediately after a short drive.
2. This fluctuating is not permanent. It bounces a bunch of times at the stop, then idles fine afterward.

Do I need to readjust the idle afterward? Someone mentioned to disconnect the electrical plug on the IACV after the engine is warm, adjust the idle screw, shut the car off, cleared out the ECU (Disconnect the battery over night), replug the IACV and resume normal operation?