There is one big hose that goes from the drivers side vent cover to the intake just before the throttle body, this one is the "pressure normalization" breather.
Then there are 2 smaller hoses, one from each vent cover, that join and go into the intake manifold on the vacuum side of the throttle body. These are the PCV hoses.
All 3 hoses have tiny holes in the vent covers that can get clogged if you ever run any oil that causes carbon and gum buildup ( can we say "Quaker State" here ? )
As long as the engine is fed a regular diet of synthetic oil ( Mobil1 0/40 ), this should not happen.