Thanks Geezer_Glider. I did some searching on the Internet and found exactly how to clean the IAC. Don't remember which site or who posted it. I just came back from a 70 ride with no more erratic idle problems. Hope it stays that way!
Here's the note I wrote so I can remember what to do next time:
HARLEY 2006 EGC ERRATIC IDLE SPEEDS FIX
Pull the air filter cover and filter off. (NO NEED TO REMOVE THE BACKPLATE ). If you look up into the top inside of the throttle body opening, just outside the throttle plate, there's a hole, about 3/8" diameter. If you look up into the hole, there's a plunger in there. That’s the Idle Air Control Valve, which controls idle speed, like an idle speed screw on a carbed engine. If you turn the ignition switch on with the kill switch on, then off again, the plunger will cycle open and closed. Put a rag into the throttle plate opening to catch as much gunk and cleaner from going into the throttle body and to keep the cleaner off the engine. Use the start run switch to cycle the plunger on the IAC and spray the cleaner into the hole with the small tube attached to the nozzle of the can, to get pressure into the hole. Keep spraying until the carb cleaner fluid runs out clear. Lots of crap was flushed out. Then re-installed the filter to lessen the chance of backfire setting your garage on fire. Then cranked her up.