Joesph,

I'll check the size of the box end socket tonight when I get home. 22mm may be the correct size as suggested by deanyel. I also just used the tire jack to lift the car on the drivers side front wheel for more working area while gaining access to the O2 Sensor. BE SURE AND SECURE THE REAR WHEELS WITH SAFE blocks and use a jack stand or something safe to secure the car while it's lifted.

Russell