<VV> NO CORVAIR Suction when oil fill cap taken off

[David Baker]

Please excuse the No Corvair post. I was hoping one of the
experts on the list might help. Today I took the oil fill cap off
my '95 Pontiac V-6 with the engine running and there was a
suction sound when I took the cap off, and the engine started
running rough. Held my hand over the oil fill hole in the valve
cover and there was a suction there, pulled my hand down. Engine
then smoothed out as long as I held my hand on the oil fill hole
in the valve cover.

The car does burn oil, could my valve guides possibly be shot
allowing the intake stroke to create a vacuum inside the valve
covers? The PCV valve was replaced a while back. Anybody have any
ideas as to what might be causing this? Thanks.

Dave