I have a 1994 Chevrolet Corsica with a 6 cylinder engine. I was looking at
the engine recently figuring out what everything was and I know that the PCV
valve sucks air from the crackcase. I then wondered where the air comes from
that is being sucked through the PCV valve. I searched for the location
where the air enters the engine and learned that it enters in through a
stiff plastic pipe that has one end plugged in at the air intake between the
air filter and the fuel injector system, and the other end is plugged into
the engine between the engine and the firewall. I then unplugged the plastic
pipe from the air intake and put my finger over it to feel the air being
sucked, but no air was being sucked despite the fact that air was in fact
being sucked through the PCV valve at the same moment. I then put my mouth
on the plastic pipe and attempted to blow air into the crankcase but I was
unable to do so. It seems as if a blockage exists that is preventing new
fresh air from entering the crankcase.

Is it possible that there is something plugged up in the engine? Am I
correct that if I blow into the plastic pipe that I should be able to blow
air into the crackcase? I cannot blow any air at all into the engine. The
thing that started all of this is that I am getting condensation on the PCV
valve, but not on the dipstick or anywhere else and my oil is clean. My
neighbor told me that it couldn't be a leaky headgasket because there is no
water in the oil and I am not losing antifreeze. Now I am thinking that
something is plugged up and not allowing the engine to breathe by way of the
PCV valve.  Thanks.