I recently noticed on a more spirited drive that when I came to a stop sign, and let off the clutch to continue a mild rattle was coming from under the car and maybe 2 feet behind the drivers' seat at about 700 to 1100 rpm. Ever since the rattle only comes back after about 30 minutes of the car running. I recently replaced the clutch so I ruled that out, I think it may be a flywheel or a DISA valve but I'm really not sure. I haven't noticed any problems with power or the transmission not shifting correctly so I really don't know what it could be.