Have you tried heating up the pipe near the sensor? Just heat the pipe, not the sensor itself. The pipe may expand enough to break the sensor free...

 

I have heard of this trick and want to try it...I just need to get a torch!

 

i haven't tried it yet, but some claim this is better than PB. Knock'er Loose.
http://www.grainger.com/Grainger/CRC...ED4?Pid=search

 

So I finally replaced that stingy O2 sensor...truck feels like it's running better already!

Would it help to reset the PCM or anything of the like?

 

1 1/8" ? weird... i tried that on the transfer case in my 1990, and it was too small.
30mm is what I needed to use.

 

Yes it will help. Disconnect the battery for a min then reconnect it.

 

What'd you have to do to break it loose?

 

I sprayed a bunch of PB blaster on it for about a day and a half. When it came time to take it off, I heated the bung with a torch and then sprayed compressed air on it...

I repeated this about a hand full of time and it came off!

BTW, use a 6-point 1 1/8" socket. The 12-point's notches are too fine to fit around the somewhat rounded drain/fill plugs.