Review on NGK Oxygen Sensor 23023 by Noah Jess

I work in a car repair shop which is a STAR station, we see quite a lot of 4.0 jeeps arriving due to smog and dropping out due to high NOX range (800-2000) after we up cat . Functions and exhaust leaks we usually find that the 02 has been recently replaced or may be faulty. For OBD1 4.0 YJ, YOU MUST have an 02 designed to work with this system. We find that many Denso sensors and even factory 02 sensors cause a NOX INCREASE as the 02 changes much faster than the systems were originally designed. We had a jeep come in for a pre-test upon request, and when we drove the jeep on top of the car we could see the NOX going through the roof (1800-2000) in the 15 and 25 mph range. After checking all other reasons for the failure, it was found that the customer had just replaced the 02, having bought NGK, an OEM supplier of ORIGINAL AMC (NOT DENSO), the car passed with no further problems. I have struggled with many other sensors on many other jeeps for 6 years and will not buy anything other than NGK again.