What would cause one bank to run leaner than the other? I have some ssautochrome headers but i only installed the front and the y-pipe but have been running them for at least 8 months and never got this code, I know these headers really don't flow any better could these be causing the problem? Could I have a bad O2 sensor even though i replaced them the same time i installed the headers? What else could be causing this problem, and just to make sure bank 2 is the bank closest to the firewall?

 

Nope, that's bank 1, bank two is the one closest to radiator.

From the FSM-

Intake air leaks
o2 sensor
Injectors
!!**Exhaust gas leaks**!!
Incorrect fuel pressure
Lack of fuel
Maf

 

try switching the front 02 sensors see if the problem stay the same.