Try the throttle hang fix and see what happens. If the throttle hang is still out of control, look elsewhere.
Some of the other things to do: clean the IAC valve, clean the throttle body, look for vacuum leaks or any other unmetered air, clear the adaptive strategy from the processor by pulling underhood fuses 4 and 11 for at least 5 minutes with a warmed up engine then drive mildly for about 10 minutes to start the adaptive relearning.
If the IAC is beyond cleaning or badly worn, it may need to be replaced.
I'm betting that cleaning the IAC and throttle body along with resetting the adaptive strategy will make a big improvement. The throttle hang fix will refine the repair.
