idler pulley, eh?
ive been pondering this for a couple weeks, trying to make sense of it all, and im back to thinking it might be the alternator. im just wondering if its not working properly after warming up, as initially the car is fine. i would imagine if it was something like a pulley it would be off all the time.
im thinking now that when they tested the alternator it wasnt hot enough to be 'failing'.
if anyone else has had funky idling, did you notice your voltmeter was reacting as well?