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!
MOUNTAINEER WITH 4.0L COMPLETE UNIT Y PIPE TEST GROUP 3FMXT04.02F7 LEV LEV1 OR 3FMXT04.02F8 LEV LEV1 OR 3FMXT04.02FB LEV LEV1 OR 3FMXT04.02FC LEV LEV1 CA OR NY APPROVED - CARB COMPLIANT D193-103 PER CARB REQUIREMENTS THE TES