EGR Valve also known as the Exhaust Gas Recirculation Valve or the EGR solenoid, This valve reduces the HC emissions of an engine by reducing the combustion chamber temperature. This is achieved by routing a a portion of dirty exhaust gasses into the inlet system. Later types are electronically operated whereas early systems are purely pneumatic. Failure symptoms are increased (CO), Poor low-speed drivability, and difficult hot starting. Failure is as a result of carbon from the engine, thus a worn engine will cause premature failure of the valve.

This part Monitors the throttle opening and closing for the ECU to adjust the fuel flow. Failure symptoms Hesitation, emissions failure flat spot or stalling when at a stand still.

Weekly Tip: Oxygen Sensor also known as a Lambda sensor, This unit monitors the oxygen content of exhaust gas to help maintain the correct Air/Fuel ratio in petrol cars.this ensures the catalytic converter is working at maximum efficiency.

Weekly Tip: Map Sensor, also known as Manifold pressure sensor, load sensor and BARO sensor. The Map sensor senses and signal the ECU, changes in atmospheric pressure and/or engine vacuum so the computer can control the fuel and ignition operation for varying altitude conditions and engine loads. Should be checked every 25,000 miles. Failure symptoms are poor engine operation back smoke, surging and catalytic converter over heating.