whell what the knock sensor does is allowing the ignition timeing to advance till the engine starts "kocking" then it will retard and try again to the max. if you retard the ignition, and you are running a "different"map than stock it could not burn all the fuel in the correct time and overfuel. the comment about lambda sensors is not true. lambda sensors work on closed loop only. open and closed loop depends on certain factors, like: trotlhe pos and map sensor. if you drive a constant rpm being 2k rpm or 5k rpm. running constant is putting the engine in closed loop. using the lambda sens