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 the non-EFI vehicles. However, since all the air entering the engine is measured through the airflow sensor, leaks in the PCV system will cause leaning of the mixture and poor driveability.