Review on 🔌 23139 NTK Oxygen Sensor by Chris Hodges

My check engine light for the rear oxygen sensor is on. I went ahead and replaced all 4 oxygen sensors (192,000 miles). Replaced flange screws @ catalog converter (leakage there probably causes light). The light went out. 2002 Jeep Wrangler TJ 4.0 L a/t If you received an OBD code for a small vacuum leak, check the gas cap. Often the O-ring in the cap wears out. Sometimes people lose lids and replace them with what they think is a suitable lid. Replace as needed. This can save you hours searching for leaks under the hood. If it was that damn cap all along. Remember that it only needs a small leak to activate the code.