What are the most common issues that can cause an Audi A3 to have a rough idle?

I recently purchased a used Audi A3 and have noticed that it has a rough idle at times. I've checked the spark plugs and air filter, but they seem to be in good condition. What other issues should I look for to fix this problem?

One common issue that can cause a rough idle in an Audi A3 is a faulty mass airflow sensor. This sensor regulates the amount of air entering the engine and can cause rough idling if it is dirty or malfunctioning. I recommend getting this sensor checked and cleaned or replaced if necessary.

Another potential cause of rough idle in an Audi A3 is a dirty fuel injector. Over time, fuel injectors can become clogged with dirt and debris, affecting their performance. Consider getting a fuel injector cleaning service to see if it helps improve your car's idle.