Clean the exhaust gas recirculation valve on your car by disconnecting the vacuum lines and electrical connections, removing the valve from the engine and soaking it overnight in carburetor cleaner. The next morning, hand-clean the unit using small brushes and pipe cleaners before drying it and reinstalling it on the car.
Remove the bolts that attach the valve to the engine. If necessary, tap it with a block of wood to loosen it for removal. Before cleaning, shake the EGR valve. If you can hear the diaphragm moving, cleaning usually repairs the problem. If the vehicle idles roughly after cleaning the valve, replace it. When cleaning the valve, check the vacuum hose and the gasket. If either is worn or cracked, replace it with a new one before reinstalling the valve.
The EGR valves on older vehicles may not have electrical connections and may work on the vacuum system alone. However, newer vehicles often have a wiring harness, which you should remove before using any cleaning product that can corrode the connections. When soaking the valve, prop it in the container so any unremovable electrical connections remain out of the cleaner. Always wear personal protective equipment, including chemical-resistant gloves and safety glasses, when working with carburetor cleaner.