[Machster50]

Originally Posted by Yal

mine turned out to be part of the air intake. There is one duct consisting of two pieces coming off the airbox. The second one connects to the engine in two places. There is a "corrugated" looking section at the top of the second section that frequently breaks down and cracks and can cause this whistle. Mine sounded to everyone like it was coming from the rear of the car, but replacing that duct fixed it right up.

Thanks Yal !!

Will check it out