The Exhaust Gas Recirculation (EGR) Valve is vital to your car's emission controls. By circulating a small portion of exhaust back into the engine, the valve keeps huge amounts of unburned fuel from being released into the atmosphere. To maintain your car’s efficiency, it’s important the EGR valve is working properly. If the EGR valve is blocked or malfunctioning, this can cause your engine to suffer. If your engine is idling roughly or accelerating poorly, ask your service advisor to take a look at the EGR valve. It could be cleaned, but once it fails your only option is to replace it. If ignored long enough, a car with a bad EGR valve will not pass emissions. From a safety standpoint there’s a slight risk, because a failing EGR valve may cause you to stall in unwanted situations. From an environmental point of view, a failing EGR valve will let harmful gases be released into the air.