Use only Acura OE quality replacement Catalytic Converters to keek your Acura MDX in the best running condition. DriveWire sells only California legal MDX OBD-II Converters.
If your Acura MDX failed the emissions test due to high NOX, the EGR Valve is most likely the issue. If your Acura is running rough or has poor fuel mileage, replace the MDX EGR Valve and gasket.
The Acura MDX Oxygen sensor is a critical part of the emmision control system and should be replaced as soon as it fails. Make sure to check the Acura MDX diagnosics codes for proper replacement of the O2 Sensor.