Commonly, the oxygen sensor is used for measuring the oxygen levels in the exhaust gases in your Porsche. Moreover, it assists the emissions control for managing the fuel injection and engine timing efficiently. Thus, the PCM in your car are using the information from the oxygen sensor to determine the right mixture of air or fuel in the combustion chamber. If the oxygen sensor is failed in your Porsche, you will notice the signs define in the following video.
https://www.youtube.com/watch?v=_ziCoorV6zk
