Whistling
If you hear a whistling sound while driving, there are a few different places you can check out to find a probable cause. The most common reason for this noise being made is a vacuum leak, due to worn or cracked hoses. If everything checks out there, consider checking if any electrical components or window seals show signs of wear and tear.
Understanding the noises your vehicle makes while in motion will come in handy as you learn more and more about how your car operates. As a precautionary measure, every once in awhile, turn your radio volume low or off, roll down your windows and listen to your vehicle while driving. The next time you hear one of these warning noises, or even one we did not mention, schedule an appointment with our shop and let our expert technicians diagnose the symptoms.
The above is what i found on internet. With acceleration going down , you need to get your car checked. ASAP.
