I am using that "spark plug extension" technique to stop my P0420 code on my 1998 LS400. I got the sensor removed. I got the extension screwed in. Now, if you have done this you realize as you screw the 02 sensor in it will twist the rubber harness to the point it's hard to tighten the
02 sensor. So, I went and tried to reverse twist the 02 sensor hoping it would work out that when I got the 02 sensor tightened there would be no twist in my rubber harness. I was unsuccessful after 2 attempts.

My question is what to I have to do to unclip the 02 wiring harness? It goes up under my floorboard somewhere. Or do I just twist the 02 sensor a few more revolutions before I try to put it back in to tighten?

I don't want to break any wires.

 

the wiring harness has a connector on the other side under the carpet. it will need to be unplugged so you can tighten the sensor correctly.

spark plug extension? so you are pulling the sensor away from the exhaust stream to trick the sensor from reading properly.
it's a good band aid but the solution might be more simple, like an exhaust leak perhaps?

 

It fixed the code. I'm just unhappy with how many twists I got in the rubber harness.

Is the connector where the rear driver's side passenger rest their feet? Is is up under the driver's seat?
Is it a bear to get to?