Sounds like i have a major vac leak when im cruising under light load but it goes away soon as i have a load on the engine or put my foor in it.. I know for a fact that the plastic cap thing on the IAC is a vac leak but i can big time here one inside the car... what the hell am i hearing?? is the iac cap supposed to suck are in around it?? tried spraying carb cleaner around and only place itreally seems to affect is the iac's plastic cap area..