Not familiar with your scanner, but I'll offer something that may or may not be helpful.

Our '94 965's gas milage seemed to have gotten slightly lower. It's my wife's car and she noted this. I noted that the oil seemed to not stay as clean as it used to; we use a fully synthetic. I asked a lead dealer mechanic about the probability of the O2 sensor needing replacement; the car has 110k miles.

He replied that he did not think that the O2 sensor was as likely as the engine coolant temp sensor at the back of the head. He said that the coolant temp sensors tend to change over time and result in an overly rich mixture. He also said that the O2 sensor is held to a fairly tight range before generating an error code, while the engine coolant temp sensor has a very broad range before generating an error code (maybe a little too broad).

I changed the sensor; a $28 part, and the car's gas milage has gone back up to what it was before (~20+ mpg general driving). It's tight back there, but it is pretty easy to replace.