Are the pre-cat and post cat 02 sensors in the OBD2a cars the same. I can't see any discernable differences in the two, aside from a little bit of heat wrap on the post cat 02 sensor. My pre cat one took a ****, from a few to many misfires, and I just switched out the post cat one for the pre-cat, and tied the pre cat one out of the way.

 

i'm pretty sure they're different. i know the pre-cat O2 is there to read and relay mixture to the ecu. post cat is only there to let the ecu know if the cat is functioning.