2010 Wagon awd, I cant get rid of the P0430 code. Had 0420 also, changed all 4 O2 sensors (bosch), both cats(one OEM GM, one who knows where it came from (was given to me with the vehicle)), the GM one is the the one throwing the code. Changed gas cap, thought it was an exhaust leak but cant find that either. Had a code for temp and changed the tstat, that went away. P0430 always comes back. any suggestions?