FU_I_AM_UltraZ

iTrader: (20)

Ok... car never threw a code til i added ls6 heads and cam on 98 t/a. after 2k miles from the swap, car must have ran a little rich with stock LS1 t/a tune and chewed up a cat... thru a code. so i put a ory to stock exhaust manifolds and new Upstream O2s and rear O2 sims. erased light with my diablo tuner from my 02 ls1 car and after 40 miles thru the SES on... tuner pulled up codes p0138 and p0158 which is high voltage O2 sensor left and right side...
So...
Are the O2 sims not working right or what?
Any help much thanks!