How many miles on your car? Is the car running OK or have a studder? The bank 1 O2 sensor could actually be bad. When did you put on the K&N CAI and when did the trouble start? Does the weather seem to have any effect, hot,cold, windy....?
my car has 52k no the k and n had no effect never through a code so i know its not that. i stored my car all winter so weather shouldnt be an issue. it did just get really hot really fast like from 40s to 100! in a week but i fixed part of my exhaust before the cat and tightened it up and i havnt thrown a code since so maybe there was an exhaust leak... hopefully