Why is my Audi A4 engine making a strange ticking noise?

I have noticed a ticking sound coming from my Audi A4 engine while it is idling. It seems to go away when I rev the engine, but returns when the car is back at idle. What could be causing this and how can I fix it?

It is possible that your Audi A4 engine is low on oil. Check your oil levels and top up if necessary. If the ticking sound persists, it may be an indication of a more serious issue and you should take your car to a mechanic.

This could be a sign of worn out spark plugs. Consider replacing them if they have not been changed in a while.

If you have recently had your oil changed, it is possible that the wrong type of oil was used in your Audi A4. Make sure the correct oil for your engine is being used.