Operation

Primary control of the system is through the PCV valve. The PCV valve controls the flow rate of the blow-by gases based on intake manifold vacuum. The PCV valve maintains a low flow rate when intake manifold vacuum is high (i.e. deceleration, low speed driving, or idle). The PCV allows a higher flow rate to compensate for increased blow-by when the intake vacuum is low (i.e. acceleration, or high load operation). If abnormal conditions arise, the PCV system allows excessive amounts of blow-by gases to flow through the fresh air tube, and the throttle body to be consumed in the combustion process.

Results Of Incorrect Operation
A plugged valve or hose may cause:
^ Rough idle.
^ Stalling or slow idle speed.
^ Oil leaks.
^ Oil in the throttle body and intake manifold
^ Sludge in engine.

A leaking valve or hose could cause:
^ Rough idle.
^ Stalling.
^ Erratic idle speed.