The EGR valve reduces nitrogen oxide emissions by recirculating a portion of exhaust gases back into the engine intake manifold. F2CZ9D475A F6ZZ9D475CA Exhaust Gas Recirculation (EGR) Valve For Mercury For Mountaineer 4.0L 4.6L 2002-2003 For Cougar For Mystique 2.5L 1999-2000. Reduced exhaust pollutants: Introducing some exhaust gas into the intake manifold and back into the cylinder lowers combustion temperature, reducing nitrogen oxide emissions. Robust & Durable: Manufactured from materials capable of withstanding heavy loads, it contributes to improved vehicle stability and responsiveness. Exhaust gas dilutes the air-fuel mixture, reducing combustion intensity, resulting in smoother operation., Manufacturer: zeshibai