I tried to fix mine but no amount of force can unscrew that sensor under the car.. I tried vise grips and o2 socket adapter and my wrench and wont budge.. im gonna have to take it to a shop to remove. much easier and im running out of time

 

did you try hot or cold? also some kind of penetrating lubricant may work...you need more moment...a breaker bar, or a big combination wrench and a hammer have always worked for me...

 

it looks like my cat on the header, I got one on order, had to be cali specific its gonna arrive on Friday or Monday next week

 

I'm pretty sure you HAVE to heat it up. I put a propane torch to it for about 3 minutes, on the pipe downstream of the sensor, and it popped right out. I did put PBBlaster to it the day before, that had no effect.

And CA specific cats are special, just like everything else in Cali. Feh.