[HoodStrype]

A cold air intake, or modified airbox will make that sound when you turn the car off... just a suggestion. Otherwise take it to the local guy and have it pressure tested. Heck, for that matter, I don't see why ya couldn't take some soapy water in a spray bottle and give it a couple of passes around the gasket. It shouldn't be any different than checking a tire. Just steer clear of the battery and distributor. If it bubbles in a certain place, its leaking. Anybody else had that problem?