I just put headers on the car and i went to remove the old O2's and the drivers was loose and the passenger is so damn stuck i cant remove even if i stand on the wrench. I think i would destroy it if i used the force necessary to break it loose. Can i use any spray or will that foul them? I was hoping to use the old ones till the new headers get broken in and don't foul a brand new one.

 

If you have access to a torch, try heating them up and then break it free.

 

Heat the metal around the sensor. Try to keep the heat off the sensor. Usually a good 30 seconds from a torch will let them loose.

 

I like heating the pipe as opposed to the sensor. Probable better chance of it surviving.