Crankcase Ventilation

When the engine is operating, crankcase pressure is used to purge vapors through the PCV valve into the throttle body. Air to vent the crankcase is drawn through a hose from the air cleaner to the right valve cover. This operation is similar to non-EFI vehicles. However, since all the air entering the engine is measured through the airflow sensor, any leaks in the PCV system will cause leaning of the mixture and poor driveability.