The O2 sensor stops working once engine is warm for 2002 Mazda Tribute.

Question

Replaced the Bank1 Sensor 2 twice and it starts out with a low live read. Then once the engine is up to temp. it flat lines. No reading.

Answer 1

The 02 sensor Bank 1 Sensor 2, Sensor 2 is the catalytic monitor sensor,If it mimic the front sensor which are engine management 02 sensor you would have a degraded catalytic convertor, As long as it is above a threshold you should be fine.