Whistle Under Hard Acceleration

[Talmadge]

I have an 02 Roadster when under hard acceleration I notice a whistle sound. Seems to be under the hood, but not sure. Have check the exhaust connections and do not see any burned areas. Do you have any idea what may be causing this. One of GM,s service bulletins talk about whistle at low RPM, my problem exist at high RPM. I do not hear this whistle each time I accelerate. Just to update this problem. I have notice the whistle sound only when the water temp. is between 200-225 and the rpm is between 4500 and 5000. This will occur if vehicle is in neutral or driving down the highway.
Thanks.:confused