that is really really strange. i mean my tuner is from am and i run the strategy tune and do not hear a knock. i mean it could be the car or the tuner. you should talk to am about sending you a new tune that is custom to try. i mean if it is both the tunes from am or on the strategy tune, well maybe try one more tune, the third times the charm. and if it works then maybe you got a bad tune. if not maybe you could try filling somewhere else, i know that shell is great gas, but maybe they got some bad gas. it is worth a shot at least. then if you get a new tune, and new gas, and it still does it then you have thrown those two variables out and it has to be something with your car.