I dont understand it, the knock sensor and harness are only 4 months old. as for the P0430 TWC LH Bank, I checked the intake no leaks, the injectors are all clicking like they should, I havent checked the exhaust out yet. This might be the problem as I was driving on some badly potholed roads this weekend with 4 friends in the car, with all that added weight I could hear my 2.5" B-pipe hitting the rear axle. Maybe it caused an exhaust leak? But would this cause a knock sensor code too come up too? Car seems to be running ok, havent run it at speeds yet. BTW the car is a 99 Cali-spec. Anyone else gotten these codes together? Thanks