Sometimes if a socket won't work I sneak a regular 7/8" wrench in there and try to get it out.
If the O2s are frozen in the pipes you are looking at replacing whatever they screw into. If they won't come out, forcing them is not going to leave you with a hole that a new one will go into.
I often price out the pipes on older cars because I see this type of thing a lot, when selling O2 sensors that is. I know it's not a fun prospect.
Sometimes using two combination wrenches will break stuff loose but it's likely your O2s are "frozen" in.
Wow all good help, thanks. I did try the torch on the pipe around the sensor and the impact but no go. I can get a solid bite on it with the box end but can't get enough leverage with that shield welded in front of it. I'll try again getting the car higher. I'll do the bones trick too for the front one thanks; see I knew you guys have heard or had done most stuff on this forum before. thanks! but in case this sensor never comes out what cat-backs work that open it up some.
They both came out!!! I did the bone trick and it worked, and the after cat I tightened it a little to break it loose with a box end and a hammer then sprayed it with PBlaster penetrant and worked it back and forth not forcing the threads and badda-bing.