Why does my Audi engine make a knocking sound at startup?

I've noticed that my Audi engine makes a brief knocking sound when I start the car. It only lasts for a second or two and then goes away. Is this something I should be concerned about? What could be causing this noise?

The most likely cause of this knocking sound is a lack of lubrication in your engine. The oil may have drained out of certain parts while the car was sitting idle, causing friction and the knocking noise. The solution is to change your oil regularly and use a high-quality oil, as recommended by Audi.

Another possible cause of the knocking sound is spark plugs that need to be replaced. As they wear out, they can cause misfiring in the engine, which can lead to the knocking sound. It's a relatively easy fix and can be done at home with the right tools and instructions.