Why does my Audi A3's engine suddenly rev up and down when idling?

I have a 2015 Audi A3 and recently noticed that the engine will rev up and down when idle, causing the car to jerk slightly. It seems to happen randomly and doesn't affect drivability. What could be causing this issue?

This could be due to a faulty mass air flow sensor. When the sensor malfunctions, it can cause the engine to receive incorrect readings, which can result in erratic idling. Consider getting it checked and replaced if necessary.

It could also be a problem with the throttle body. If it becomes dirty or clogged, it can cause inconsistent airflow and lead to issues with idling. Try cleaning it first before getting it checked by a mechanic.