So you have the same problem as this guy ??
https://www.youtube.com/watch?v=QYr9nloWzoM You can check the vacuum servo (actuator) by using a hand pump like a Mityvac
and applying vacuum directly to the actuator. If the servo cannot hold vacuum and
leaks down in just a few seconds, then the diaphragm has split.
If the servo holds vacuum OK, then the next place to look is for excessive play in
the linkages. If the butterflys are free to move by even just one or two mm when
the servo has retracted, then intake pulsations will make the linkage rattle.
If you can find a way to get a length of string around the linkage so that you can
tie the butterflys firmly closed, then you can check if the noise goes away. Try this
first if you don't have a vacuum pump close by
Cheers... jondee86