im thinking i have a vacumm leak. i can hear something from what sounds like under the intake manifold. now i dont recall having any vacuum sourced under there but the pcv valve. it might be leaking at the intake manifold gasket to head. so i was just thinking to test for leakage i would unplug the iacv and tun the screw all the way in and see what happens. any other good ways to check for leaks instead of using some spray thanks