[Discseven]

Chris,

I replaced my O2 with the exhaust out and it was a bollywood production... Eventually resorted to cutting the wires off the sensor, making a metal mask to allow the seat area to be heated and the sensor to be cooled. Used a long socket and a huge vice grip (major leverage). Before anything I beat the sensor (respectfully) a number of times in hopes of breaking some adhesion.

By heating the sensor's seat area and cooling the sensor itself, it eventually wrenched out (with significant leverage.) 2 people required --- one to hold mask and cool sensor with wet rag... the other to torch seat area. Obviously this path won't work with parts installed on the engine.

Thinking now... had that not worked, perhaps the sensor could be cut off and the remainder drilled (carefully) out. A bit risky.

You might want to post in the "engine rebuild" section --- those guys deal with stuck stuff all the time.