Engine "hiccups" at idle

While I'm waiting until Monday for the local AAMCO to open up, I was wondering if someones could help me diagnose what seems to be an idling engine problem. Occasionally at idle the engine will sort of "hiccup" or "burp," like it's about to stall (but doesn't). It's only happened twice in three days since I've had the car back, and does it while it's warm. I cleaned the throttle body about three weeks ago; but maybe I didn't do a good job? I've searched the board but didn't really find anything quite like this (although I would think it would be a more common problem?) Please help, thanks