Has anyone ever had problems with the 02 circuit? I went up to autozone and got my check engine light scanned and it was showing that it the 02 Circuit. I'm having trouble finding what is wrong, and I honestly can't tell that anything is not working properly. Does anyone have any idea? Thanks in advanced

 

My heating eliment in my O2 sensor is dead and it throws a code for that every time I clear it. Right now my engine is running fine but gas mileage could be better. Do you have any hesitation problems pore MPG?