Repair Procedures: Inspection

After disconnecting the vapor hose from the PCV valve, remove the PCV valve.
Reconnect the PCV valve to the vapor hose.
Run the engine at idle, then put a finger over the open end of the PCV valve and make sure that intake manifold vacuum can be felt.
NOTE: The plunger inside the PCV valve will move back and forth at vacuum.

Fig 1: Checking Intake Manifold Vacuum
Courtesy of KIA MOTORS AMERICA, INC.
If the vacuum is not felt inspect PCV operation, if operating correctly clean or replace the vapor hose.