My 2000 WJ threw a code for an 02 sensor at 254K miles, Bank 2, sensor 1. I replaced it with a Bosch. At 260K miles it throws a code for Bank 1, sensor 1. How much more can I ask from original parts?

Oh! And the cats are original too, even after being on an engine that burned oil. I did use Cata-Clean just before swapping the engine though.

 

Seems I've read that the sensors must be within a particular range (spec) of each other or a CEL will happen. Vehicle will perform fine though. Also if I remember right it was suggested both be replaced at the same time if one goes out.

 

Yes, I'm aware of that. I do get a slight roughness in the idle until they warm up, but that just started 2 days ago. This morning I got the CEL.

 

I think you did very well. If you get 150k, you are doing okay.