[paulicat]

Its actually hard to describe this one, its a metal on metal sound, the closest thing I can think of is the sound you'd get if any part of your exhaust system were to be too close to the floorboards (or any any part of the car). So when I accelerate, the torquing of the engine causes it to move enough to make the knocking/rattling/vibrating sound. For the life of me though, I don't see the exhaust being to close anywhere from the front to the rear of the car.
Prior to the mechanic looking at it yesterday, the exhaust was definitely rubbing against the big heat shield that is located in the exhaust tunnel, but he cleared that out of the way. I was underneath yesterday and moved that exhaust a bunch, but could not get it make ANY sound at all.
Rather frustrating.

What were you suggesting with the marble sound though so I can check that out just in case?