Hello.. I am new to the forum and I have an 03 passat, auto, 4 cyl automatic. When I accelerate in drive, and even increasing the rpms in neutral, there is a high pitched sound coming from the engine. It is not a rattle or a clunking sound that alarms me, but it is different. Since the weather has changed to colder I have noticed it more, and there is not much evidence outside of the sound that there is a problem. It is more like an exagerated, high pitched hissing sound (for lack of a better term) that coincides with the rpms. Anybody with a similar problem and a possible solution would be helpful. Thanks.

 

That might be an exhaust leak.