PCV has whistle and/or whine
15-16 inches of vacuum!! I have two engines one in my Ram and the other in the cuda. Neither one pulls over 10... lol
Could use process of elimination. Remove and plug off PVC. Drive it. Just to eliminate the possibility of the whistle coming from somewhere else.
Put tape around the PVC where it goes into the grommet. Put tape over the perimeter of the grommet. Tape it up air tight and see if it still whistles.