Help! 88 GP o2 sensor prob!

Hi all.

Horrible problem I'm having with my car... o2 sensor needs to be replaced. Only problem is that on the 88 2.8L Grand Prix, it's on the manifold, with no easy access to it... I can get a wrench around it, but there's no room to move it, much less put the necessary torque behind it to actually pull it out.

I've gone through my Haynes manual, which is strangely silent on the replacement of the sensor, only saying that it should be done as part of a major tune-up (helpful, huh?).

I've taken the two front engine supports off, pulled back the engine and placed a brick along the back end of it, so as to give me some room at the back (swivelling the engine, as the book suggests to replace rear spark plugs/wires).

Any thoughts? I'm dying here.

Thanks.

Mark.