ok i have a 99 se cali spec its been sputtering and driven rough. i bring it to mechanic and he says cant do anything without a cel. so ive been driven it and doesn't do it all the time anymore but still a lot. the cel comes on today and i bring it to autozone and they said it was bank 1 o2 sensor which i think is front closest to you facin car. but thats the one i replaced. could it be bad or is it the rear one? please help its makinme want to trade it in.