[desolate]

That would be phantom knock. Technically what causes that noise are from the lifters that is picked up by the knock sensor. I believe what he's trying to say is the knock sensor would not just recieve noise from nothing. Although in my past experience I drove a 92gsx with horrible lifters. At the time I was logging the car and found out that even though the noise from the lifters was loud, I wasn't getting any 'phantom knock'. Strange, but it must be different car to car.