my car is a 2014 chevy ss (holden) ls3 with 2 in headers btr stage 2 and a roto fab. exhaust is catless ive been in open loop for the last 2 years but i recently put the o2 sensors back in and put into closed loop just to see how far off i am and although my bank 1 is pretty close my bank 2 stays about 5 percent richer than bank 1. is this normal?