Figured as much.

So why were you looking for a new O2 sensor, because of the header installation, or was it throwing a code?

 

both lol. it was throwing an 02 code when my truck started to run like crap. which i figured was influenced by the fact that i have a broken bolt in my manifold which in turn caused a manifold leak which in turn messed with the sensor...thereby making my truck run like crap.

as far as the down stream sensor...its just plain, not there. nothing attached. just a hole with a plug in it. never gave me any problems before, and i dont believe i have a 02 sim at all.