So it's the actual sensor that threads into the block? Try a little penetrating oil, and if you can find a socket that fits on it, preferably a deep walled and a breaker bar. C
at the point its stuck and probably going to break and need to be replaced get out your channel locks, vice grips, hell anything that can get a hold of it. If it will not come out in one piece, it will still come out.
Hold on now, guys. Dont forget OP is in the 2v section. He might have the all plastic intake or even the aluminum cross over. We dont need go and put a whole lot of force on this thing. We need to find out exactly what needs to be done.
Is the sensor smashed and holding the electrical connector in it?
Is the sensor broken and seized up in the intake manifold?
Sorry for no pics guys, im on a phone and couldnt figure out how to post them. I ended up just picking away at the remainer of the green insulation and found an easy out that fit. I had the aluminum crossover