Also when the noise stops it confirms the solenoid is good and working. You don't have to take the plenum off but you do have to take the timing belt off. If you still have your old timing belt there's a certain way you can wrap it around the gear to hold in place to while you torque the gear bolt. I believe the instructions for that are somewhere on this site. It's hard to explain without pics. let us know how your test goes. good luck.
