Why is my Audi A3's engine making a loud knocking noise?

My Audi A3's engine has started making a loud knocking noise that seems to be getting worse. It only happens when the car is running and increases with acceleration. What could be causing this and how can I fix it?

It's possible that your engine's valves are out of adjustment. This could be causing the knocking noise and can potentially lead to further engine damage if left unaddressed. It's best to take your car to a certified mechanic for an engine inspection and adjustment.

Check the engine oil level and condition. Low or dirty oil can also cause engine knocking due to lack of lubrication. If the oil level is low, top it up and consider getting an oil change if it's been awhile since the last one.

Another possibility is that your car's fuel octane rating is too low for your engine. Try using a higher octane fuel to see if the knocking noise decreases. And remember to always use the recommended fuel type for your car.