The exhaust gas recirculation valve, typically refered to as your car's EGR valve, is one of those parts that most car owners will be completely unaware of unless they experience a problem with it. The EGR valve's main job is to control the formation of nitrogen-based gases and emissions from your engine. A dirty or clogged EGR valve will cause your vehicle to run improperly
If your EGR valve is dirty or clogged, your engine will not idle well. Coughing, sputtering and choking while idling are all possible signs of a clogged EGR valve. When the EGR valve is dirty, it may become stuck open and affect your car's ability to idle.
If your car is routinely stalling, your EGR valve may be to blame. Because of the way the vacuum works to control airflow between your intake manifold and your EGR valve, too much vacuum can cause your EGR valve to open completely and stall your motor.
The "dirt" that clogs your EGR valve and intake manifold is not dirt in the traditional sense. The dirt in this case is carbon buildup from your engine and emissions. When the carbon builds up to a certain point, it hardens and forms a residue. This residue will ultimately clog your intake manifold and EGR valve, stopping them from functioning properly and causing the rough idling and stalling.
