after 3 trips to the advance zone for the correct fitting O2 sensor without the correct fit. I'm willing to try cleaning the original. Is it worth my effort or not?

 

Before you do that, try swapping the sensors side-to-side, see if the fault moves with the sensor. If not, your catalytic converter may be done.

 

The cat was replaced about 1200 miles ago , suffered an internal involuntary disassembly. Unknown if the sensor was also replaced at that time. I’ll perform cleaning, reassemble and then swap test if necessary .

 

I've never had success with cleaning an O2 sensor. Of course I've only tried it a couple times though.

 

Would one clean an O2 sensor, with oven cleaner?

 

I used fuel injector cleaner, non-diluted. It worked for at least awhile although I can't remember for how long. Maybe even until I sold that car???

I'd be up for oven cleaner, a failed one can't get any more failed...

 

Should be able to get correct aftermarket replacements at Rockauto. Your local parts shop probably doesn’t see a lot of Jaguar owners.