Disconnect the ground cable and touch it to the positive cable. That will reset the CPU. If you still have a high idle, BUT the idle drops, just not low enough.... Try replacing the coolant temp sensor at the water neck (apx $20.00).
I fought this for a while swapping around TB's and IAC's before I replaced that sensor. My temp gauge worked so good that I was even able to see a ten degree decrease when I overhauled the cooling system, and it remains unchanged, but it fixed my high idle issue.
Mine would run at 1600 and drop to 1200. A CPU reset would fix it for a week, then a few days, then one drive cycle. When reset, it would be at 1100 and drop to about 600. Drive me nuts, but the coolant temp sensor did the trick for me!