Hey, what Kilgore trout said, plus, when I put my catch can in the vacum was to high, and it started to suck fresh oil off of the bearings w/ a loud squeal, so I capped off the the upper plenum w/plastic hose and a metal stopper that was provided to me. But, I was still getting blow-by in my upper intake, so I got a second pvc stuck in a larger rubber hose, much like the one the IAC is connected to, and a metal ring to slow down the vacum suction, now if your car runs rich often then you are going to get a light brown sludge blow-by but the second Pvc should take car of that, "walla" only the gas fumes get by. It takes some custom work to get the vacum just right, whats provided w/most catch cans is not enough. It works fine. Or you can just put back your oem pvc system, but its not as affective as the catch can, plus your emmissions are going to higher!