What causes the engine to idle rough in a Kia Rio?

I've noticed that my Kia Rio's engine idles roughly at times. It's not a constant issue, but it has been happening more frequently. What could be causing this and what steps should I take to fix it?

The most common cause of a rough idle in a Kia Rio is a dirty or clogged air filter. This can restrict the airflow to the engine and cause it to run rough. Try replacing the air filter and see if that improves the idle.

Another possibility is a faulty ignition coil, which can cause the engine to misfire and idle roughly. You may need to have the ignition coils tested and replaced if necessary.

Have you checked your spark plugs recently? Worn or fouled spark plugs can also lead to a rough idle. Consider replacing them if they are old or damaged.