Ive been having an issue lately, once my car is warm as i come to a stop and put it in neutral (manual trans) the idle will drop low enough to almost stall for a couple seconds and then go back to a normal idle speed. occasionally it does stall. anyone have any thoughts?

i was gonna pull the IAC and clean that up. i also sprayed carb cleaner around the intake and vacuum lines and didnt seem to find a vacuum leak.