I think mine has issues...so let me describe what I see/hear. Maybe others can chime in.

If I remove the engine cover and then start the car, the following happens. Where the rod goes into the plenum, I hear what sounds like a vacuum leak or air being sucked in. When the plunger pulls back (which it seems to do every 30 seconds or so) the air suction sound disappears and I hear a clicking, like a loud tick. I hear this same sound when driving (near an object or wall where the sounds bounce).

As of right now, I can tell the car has low power around 3K RPM and around 4K it comes alive. I think this means the valves are working.