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 UP TO 03/01 /04 - Y PIPE CONVERTER ASSEMBLY 3 CATS EXCLUDES SPORT AND SPORT TRAC FEDERAL EMISSIONS CONVERTER WILL WORK WITH FEDERAL EMISSION SYSTEMS. NOT FOR SALE OR USE ON VEHICLES REGISTERED IN THE STATE