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 store that showed a code of PO138. They told me this indicates a ...

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 ...

What could be the reason for your car to fail a pollution test? While there may be many factors, one of the most common problems is that the vehicle hast run long enough to warm up the catalytic ...