GM service writer called and said I needed a $250 Post Catalytic Converter Oxygen Sensor for my 2001 Chevy Cavalier. I took the car in because the Check Engine light occasionally comes on. The catalytic converter was replaced in April but not the Post Catalytic Converter Oxygen Sensor. This part was not replaced at that time because it was not showing defective.
Can I just NOT replace the Post Converter Sensor? What can I expect if I do not replace this part?
Thanks
Tim