Anyone replace their own pre-cat o2 sensor?

[Evil8]

My b1s1 (rear sensor on the exhaust manifold) sensor is bad. I can touch the tip of the sensor from underneath the car but the heat shield prevents me from getting a wrench on it. The short manual briefly describes replacing it when removing the engine. There's got to be a way to replace this thing without dropping the engine cradle!

Any insight?

[Wintermute76]

Only thing I can say is to be prepared for a major hassle.
The manifold sensor on my wife's old Altima was seized/eroded/welded right to the reducing bung in the manifold.
After breaking off the top of the sensor, I was able to get a real socket on and with a 3' cheater on my breaker bar, the bung and sensor came out as one piece.
Ended up single pointing a new reducer out of stainless.
And this one was right in the open. There was about 175k miles on it.

With luck, yours won't be as bad.

[Warhammer]

I think this one is best left to he mighty Turbizzy. He's a certified Nissan technician that has probably done this kind of work before.