[2000SoCalBoxsterS]

I have a code reader and a list of the definitions for these codes from three different sources. Typically I've seen advice that these CEL codes are probably a bad or dirty MAF. But my question is, why does the actual code definition say it involves my O2 sensors? Should I replace all four of my O2 sensors? I hear they are about $130 a piece.

I cleaned my MAF today what are the chances that will take care of my CEL problem?

Engine bay & dirty air filter


The MAF. You need a T-20 Torx Security tip (Tamper proof) to remove the two screws.


Hole where the MAF used to be.


The MAF. This thing cost $250 online $400+ from the dealer! I sprayed electronic parts cleaner on the contact points. The paper clip looking thing.