I understand what you guys are saying... my point is that i myself have NEVER heard a stock civic si w/b16 hisss like my car does with the idle screw somewhat open. ALso, with the idle bleed screw open, ive noticed that when cruising and letting off the gas to come to a stop, the rpms wanna hang much higher due to the additional amount of air being let in past the throttle plate. This doesnt seem right to me. Heres a few of things that I think could be causing it..

-faulty throttlebody gasket (internally)
-faulty Fast idle thermo valve
-faulty ECU
-faulty or dirty injectors
-incorrect ignition timing

Could any of these be causing this condition? I fail to see the point of disconnecting the iacv when setting the idle.. how would that change anything? the thing is computer controlled...? Thanx for the help!