Add Yahoo as a preferred source to see more of our stories on Google. Q: In my vehicle, the check engine light comes on and then goes off and it is now back on. I had a test done at local auto-parts ...

I had a test done at local auto-parts store that showed a code of PO138. They told me this indicates a problem with the oxygen sensor. I replaced the oxygen sensor and the light never went out. I ...

The "Check Engine" light is the most feared dashboard notification, but for the Oxygen (O2) sensor, it is a lagging indicator. By the time that light illuminates to tell you your O2 sensor has failed, ...

Your car's O2 sensor can cause rough running, bad mileage, and inspection nightmares. Can a quick clean save the day? Here's what you need to know.