I had that valve out while changing the elbow and it looked great. I have also read that if it fails it will be a constant hamster wheel spinning sound. I am assuming that either this brief whistle is normal or it's a vacuum leak somewhere else. Or could it simply be an air vortex sound thru the small tube portion of the intake elbow during low rpms? Does anyone else with a 3.0i hear a slight temporary whistle from the engine bay when accelerating from a stop? Thanks Greg