From your description of the problem it might not necessarily be an O2 sensor. A rough diagnosis of the O2 sensor is easy. Just monitor the voltage that it is putting out while idling. If the voltage is bouncing around randomly between 0-1V it is still OK. If it is sitting still when the car is warm it is shot.
I would also look into new plugs and wires and a boost leak test. If it were me.
I would also look into new plugs and wires and a boost leak test. If it were me.
