i no where it is! mine did it! if u put your car on a ramp or pit n get underneath, where the de cat comes down from the engine,then sort of begins to come in line with the rest of exhaust(mines got some form of silencer/box on it) the top of that catches on some sort of heat shield on the floor of your car, just bend the shield upwards a bit.if u have a look, i think it will be quite obvious mate.
however,....... that was the first time i fitted it.last week i put it back on again and now, it rattles somewhere else....i dont no whether my exhaust is catching on my back bumper or not?it sounds like it!its annoying!but then again its a renault!
Paul