yesterday i got to drive my mustang to my girlfriends house. was coming down a hill not giving the engine any gas and at about 60 its starts to knock, i stepped on the brakes a little and it stopped? what can be causing this?
Since the brakes don't have anything to do with internal rotating parts, it's probably just something loose that was making the noise. I'd start by getting under the car and checking everything out. If you keep hearing it, try to relay a little more to go on, and you will probably get numerous suggestions. Keep us posted.