O2 vs LC-1 Calibration

I recently noticed that my OEM O2 sensor and LC-1 wideband sensor in my DP were no longer reading similar values. My LC-1 used to be ~.25 richer than my O2 sensor, but not it is almost ~.9 richer. I have tried calibrating the LC-1 twice (using SW and manual push button), but the results are the same.

Any ideas on what sensor I should look to replace?

In general, I would look to trust the after market o2 more than the potentially 15 year old narrowband on the car itself. That being said, you need to verify. I would look into doing one of the following to verify which sensor is correct:

-Take your car to a dyno that is equipped with a wideband and see what its readings are vs what your seeing. A professional dyno SHOULD be keeping their widebands up to date and accurate.

-Borrow a friends wideband and install it on your car and compare the numbers of your front o2 to your wideband vs their wideband.

-Install your wideband onto a friends car with a known good wideband and compare

Which ever 2 sensors read the closest are likely the more accurate reading. Also keep in mind placement of the sensor in the pipe can throw off the readings as the further down the pipe you have the sensor mounted, the more it should read slightly leaner.

Good luck with your findings.