A car's engine depends on a balanced ratio of fuel and air for proper combustion and sufficient horsepower. A faulty exhaust gas recirculation (EGR) valve affects the functioning of the mass air flow (MAF) sensor for an engine's air flow.
The EGR valve allows a small quantity of exhaust gas from the combustion chamber into the engine's intake manifold, resulting in a cooling of combustion fumes. The MAF sensor, also known as the air flow meter, calculates the amount of air entering the engine for balancing with the fuel.
Typically, a faulty EGR valve leaks more gas into the engine's intake manifold, which has a direct effect on the MAF's functioning. The MAF detects more gas or air within the system and automatically adds more fuel to the mixture to balance the fuel-to-air ratio.
A faulty EGR valve requires immediate replacement. Aside from wasting excess fuel from an improper fuel-to-air ratio, a faulty EGR valve releases harmful emissions into the atmosphere.