Im trying to replace my o2 sensor but i cant get it to loosen.
Any ideas?

 

Run the engine for a short time so it is moderately hot and try again. If still no go, put WD-40 or PB Blaster on it while cold and let soak for at least a few hours. Finally you can cut the wires and/or break the outside part of the sensor off so you can put a properly sized deep 6-point socket over it then really wail on it with a breaker bar.

 

is the sesnor bad, or are you just installing a header or something? If its bad, use all the lubrication you want (since the sesnor is alreayd ruined), and the socket idea mk had is a good idea too

 

Cool I was thinking about doing that but i figured i better ask b4 i went choppin wires.
Thanks I'll give it a try.

 

If you're sure it's dead you have nothing to lose destroying it further. If you do use spray on it, be sure to clean it all up before putting the new sensor in. For example put what's left of the old sensor back in the hole loosely and run the engine to burn everything off.

 

Got the old one out and the new one in. No check engine light but now im getting the 41 code. Thanks again for yalls help.