[JFP in PA]

Porsches have "restricted code" areas in the computer (as do many other makes) that a general purpose OBD II scanner cannot see or clear. These require more specialized equipment that either a Porsche indie shop or the dealer will have. Get the codes read and write them down. Let us know what they are and they can be deciphered for you.

As for the O2 sensors, no, they are not hard to replace; but they are probably the most misinterpreted sensor because the way the codes read out, which confuses the uninitiated into replacing them when that is not really the issue. Get the codes.............