it makes a change that someone else gets the nightmare jobs, thought it was just me.although not relavant to this vehicle i have had misfire codes for 1+2 with slight uneven idle,turned out to be worn keyway on crank and pulley,this upset timing slightly threw cyliner codes and could cause knock sensor code,? like i say not on same car and not sure on yours were crank pick up is, but worth checking timing related items.