Ok My Protege failded anual NYS emissions test, I took it to Auto zone Got a code for o2 sensor Bank one sensor 2 , i bouthg the sensor they only show before or after the converter, they dont show bank 1 or 2 on their computer, so i figure is bank one the sensors before the cat converter? i dont want to replace the wrong one. Can anyone please let me know, THanks,

 

I do not know how they would say that you need a Bank 1 or 2 O2 sensor, since it is a 4cyl. Just for kicks though, I would probably go with bank 1 being at the manifold & 2 being at the converter.