What is the most common cause of a misfire in an Audi A3?

I've been experiencing a persistent misfire in my Audi A3, causing sputtering and loss of power while driving. It used to happen occasionally but now it seems to be happening more frequently. What could be causing this issue?

The most common cause of a misfire in an Audi A3 is a failing spark plug. As spark plugs age, they can become worn and dirty, leading to ineffective sparking and resulting in a misfire.

Another potential cause could be a faulty ignition coil. The ignition coil is responsible for supplying the spark to ignite the fuel and air mixture in the engine. If it malfunctions, it can lead to misfires in one or more cylinders.