I was reading on supersixmotorsports.com
about PCV valves and wondered about the one on my truck, assuming that is what that little plastic hose is running to my intake. PCV valves let oil into the air/fuel mixture lowering the octane rating. I was wondering does the 4.0's have any oil in the air mixture. Would i benefit by closing off the PCV valve with a breather and blocking that hole on the intake?
heres the .pdf i'm talking about.