put a new cap and rotor on my 97z about 300 miles ago put it away and the computer said it was bad so i'm changing it and curious me took it apart and its corroded and rust dust everywhere was this a vacum issue.
Shawn

 

How many miles on it? Common for the bearing to wear out and cause dust inside. That's why it is not so efficient to just replace the cap and rotor. You should, however, make sure the vent system is functioning correctly.

 

Rob,
50k on the opti, couple hundred miles on the cap and rotor. I was playing with the 2 check valves in the vacum line and it seemed they were in opposite directions?
Thanks Shawn

 

Not sure that the big valve has a direction, but the smaller one should have the blue side toward the intake manifold. pic