Why is my Audi A4's engine making unusual noises?

I recently noticed that my Audi A4's engine has started making strange noises when I accelerate. It almost sounds like a knocking or rattling sound. What could be causing this and how can I fix it?

This could potentially be a sign that your engine oil needs to be changed. Dirty or low engine oil can cause the engine to make unusual noises. It's always a good idea to follow the manufacturer's recommendations for oil change intervals.

It's also possible that your engine's timing belt needs to be replaced. If the timing belt is worn or loose, it can cause the engine to make abnormal noises. Check your owner's manual for the recommended timing belt replacement interval.

Another potential cause could be a problem with the engine's components, such as the spark plugs or fuel injectors. It's best to have a professional mechanic inspect and diagnose the issue to determine the exact cause and recommended repair.