02 sensor (upper)
 

so i tried my hardest to get this off. I couldnt!!! Is there a trick? It wouldnt budge. And i have an 02 bonnie, and its the one up top before the cat. I may be a woman, but dang, i couldnt get it to budge.

I think I may have used a 24inch breaker bar and done it after it sat all night.

If you are replacing it, try some penetrate oil like BreakFree or WD40. You may have to soak a few days. Hopefully you are using an O2 socket or wrench. If this is the first time replacing it, you will definitely need to put some brute force into it.

Yeah, maybe try a penetrating lube.
I would recommend some mechanical advantage. ( longer rachet, air tools etc )

I soaked mine for a good week with penetrating oil before it finally broke loose.

I just did my SEEi and my Monte SS within the last month.
The Bonne's came out really nice, but the Monte's put up a fight. I ended up crawling up on top of the motor, put a longer rachet on with a taller extention and braced myself for the inevitable impact after I got it loosened up. The scars are healing, and the Monte's never run better. :-)

so like everyday for maybe3 days put some maybe liquid wrench on it? Should i just drive regularly as well? Would that be fine? and then after a few days of using pent. oil, try to get it out? I talked to someone and they told me that i may need to re thread it since it is a PITA to get out. And how hard is it to rethread?

Ya, just do that. I picked up a thread cleaner from autozone. It goes in a socket and turns right in nice and easy.

thread cleaner? is this a penetrating oil?

No, it's like a thread tap. You run it in to the bung and it cleans up the threads.