2014 A4 OWNER

I'm not sure exactly what the oil change interval is about 60,000mls sounds reasonable, when was the last time it was changed? Getting the oil changed solved my problem. Its not cheap though, and not all garages have the required tools/knowhow. I hope this helps.

My only advice would be:- don't just go getting something like a K&N cylinder/cone type air filter, they are not as good as you may think, because it's drawing in warm air from the engine bay, "where the hot engine is". Buy a performance filter that fits into the original ducting, that channels cold air from outside the car, or cut into the bonnet and fit an air scoop.