A faulty Oxygen Sensor is a primary reason for Failure of a Catalytic Converter. Car Manufacturers Recommend Replacement of O2 Sensors at 60,000 miles. If you are purchasing a New Catalytic Converter be sure the Oxygen Sensors are Checked and Operating Correctly!
MARINER WITH 3.0L REAR EXHAUST MANIFOLD WITH INTEGRATED CATALYTIC CONVERTER FIREWALL SIDE BANK 1 TEST GROUP 5FMXT03.01FE LEV1 ULEV CA OR NY APPROVED - CARB COMPLIANT D798-9 PER CARB REQUIREMENTS THE TEST GROUP SHOWN HERE MUST MATCH THE TEST GROUP OF YOUR VEHICLE.