I have two aging 2003 Montero Limiteds with 4 sensors and 3 catalytic converters. Both have about 203,000 miles on them.

I'm getting a Bank 1 upstream O2 sensor failure on one Montero and a Bank 2 upstream sensor on the other. Both are running with their respective P017x OBD-II lean code. So exact issue but different banks.

I thought about taking one good upstream and swapping it to the other Montero to see if actually worked to fix issue (can you hear my doubt? Lol) but then I thought about just deleting the lean code and unplugging all 4 sensors (upstream and downstream) and see if operation improved over a tank of fuel economy. Many folks have replaced sensors with new Denso or NGK and the problems don't go away OR they get worse.

Online, for other makes and models, I'm seeing this works for some and their older vehicles run better.

Has anyone tried this? If all other systems are working well, what would this do to general operations ya think?

 

I cannot speak for the Montero but I have a 2021 Outlander Sport with 2.0L engine and the catalytic converter was stolen last month along with both the upstream and downstream O2 sensors. I installed a new cat but it was several weeks before I could get a downstream sensor and I still haven't been able to get a new upstream sensor. But without the sensors the car ran just fine. There was no change in either performance or mpg. The only change I can see is that the service engine light is on.