What is the cause of the rumbling noise in my Audi engine?

I have recently noticed a rumbling noise coming from my Audi's engine. It seems to happen when the car is idling or when I accelerate. I'm concerned that it may be a sign of a larger problem. Can anyone provide insight into the potential causes of this noise and how I can address it?

The most common cause of a rumbling noise in an Audi engine is worn bearings in the crankshaft and connecting rods. It is recommended to have the bearings inspected and replaced if necessary.

Another potential cause of the rumbling noise could be a damaged or worn out exhaust manifold. It is best to have a mechanic take a look and make any necessary repairs.