Well, when you bumped the idle speed up did you reset the computer? Anytime you change the idle speed via the idle stop screw you should reset the comp. Keep in mind this will reset the codes, so make sure you pulled the codes first.
There are other mechanical issues that can cause your symptoms. The ECT (code 21) and the TPS (code 23). When you bumped the idle up, it's possible you moved the TPS out of range. You'd see a code for this in the KOEO codes. If it's there, you need to readjust the TPS below 1.1V at idle. The range you are shooting for is between 0.6v and 1.1v...no specific number, just anywhere in there.
Try this. First, clean the hell out of the IAC with carb cleaner and make sure everything moves nice. Bolt it on, but leave it unplugged (to prevent the computer from trying to control idle). Next, remove the spot connector to lock timing in place. Start the car. If it wont start, open the throttle screw up until it starts. Once started, adjust your idle to where you want it to be. Usually you want it at the lowest sustainable idle, but if you want to bump it for your a/c, set it up higher. Once set, turn off car, unplug battery for 30 mins and plug the IAC back in along with the spout. Hook batt up, turn key to ON and verify the TPS sensor is in range (0.6-1.1v) Start the car, let it idle 2 mins without a/c on, then 2 mins with a/c and other accessories on. This is the proper idle reset procedure.
Anytime you touch the idle stop screw, you much do the above procedure. Failure can give you an erratic idle like you have. Also, run the codes after a few starts and verify you dont have a TPS out of range code.
And FORD IAC and TPS sensors (or any sensors for the matter) are better than parts store sensors
good luck