well i had a CEL and i went and got it tested and it was the o2 sensor. It said BANK 1 SENSOR 1. which one is this before cat or after cat? i think its the after but just double checking. any help would be great. Thanks

 

Probably the one in front, that would most likely go out first because it is exposed to moree. Case closed

 

bank 1 is the side of the engine that the sensor is on for instance v6 or v8 left or right side. being a 4 banger we dont have that problem sensor 1 is b4 the cat and 2 is afterthe cat.

 

sensor 1 is pre-cat, sensor 2 is downstream of the cat.