any idea how to remove the o2 sensor?

 

Un plug the connecto and I beleive it is a 9/16' wrench or 5/8' to take it off. If it is stuck spray some WD40 onto it and let it sit for an hour or so to let it sink in. When installing the new one make sure you use some anti-seize compound on the threads of the new sensor. Reconest the wire and clean up any WD40 so it doesn't smoke.

Replacing an O2 sensor is one of the easiest jobs to do when a wrench is needed, just make sure you are replacing the right one. Bank one is before cat and bank two is after cat.