I just thought of this one and figured it might get a few laughs out of some people. I have 2 (yes 2) 1st gen 4 runners, both 89. The one I'm driving is a 3.0, and the parts vehicle is a 2.2. Both have the same o2 sensor on them, and both appear to be WELDED to the studs. I thought at first someone might have tried to remove the nuts and rounded them off in the attempt, but upon looking at the parts vehicle, it was in the same condition. If I take a closer look, it actually does look like a weld... anyone got any thoughts on this, or an easy way to remove the sensor. I could put a new bung on the pipe, but I don't have ready access to a welder...

 

Man, remind me not to come to your n'hood for fear of breaking down and needing some repairs.

Likely, the nuts were sheared off by some lazy goober. Now what he said, well the only option is to weld the new one on......not gonna buy a new pipe to fix this......

I would pull the pipe, drill out the broken studs and tap the holes. Get a 2 inch long metric screw as a replacement and cut to the desired length. Use a lock washer.

My $0.02

 

now what would the chances be that bothe repairs were done by the same goober?

 

haha you never know!!

I also have an 89 runner and my 02 sensor was welded in as well! sad but true.. I went to change the 100 year old sensor and took the easy way out and bought a new intermediate pipe that goes from the exh manifold to the cat.