4.6 LITER. front. OXYGEN SENSOR AND RELATED COMPONENTS. VAPOR CANISTER. Check Valve for Emission System. Exhaust Gas Recirculation (EGR) Vacuum Delay Valve. From Engine # 5XXXXXX. Location-Engine Bay. To 09/2020. To 11/2017. To Engine Serial # 4XXXXXX. Vapor Canister Purge Solenoid. Regulator. Switching. Air Switch. Control Solenoid. Emission Check. Exhaust Gas Recirculation (EGR) Delay. Vapor Canister Purge Solenoid.