Why is my Audi A4's engine making a strange noise during acceleration?

I recently purchased a used Audi A4 and have been hearing a strange noise when I accelerate. The noise sounds like a low rumbling and only occurs during acceleration. What could be causing this and how do I fix it?

It sounds like your engine's serpentine belt may need to be replaced. This belt helps power many of your car's components, so when it starts to wear down it can produce a low rumbling noise. I recommend taking your car to a trusted mechanic for a diagnosis and potential replacement.