What could be causing the rough idle in my Kia Rio?

My Kia Rio has been idling rough lately and I'm not sure what could be causing it. I've checked the spark plugs and they seem to be fine. What else should I check?

It could be a clogged air filter or a dirty fuel injector. Try cleaning both and see if that improves your idle.

Have you checked your ignition coils? They can sometimes cause rough idling. If they're worn out, consider replacing them.

Bad oxygen sensors can also cause rough idling. Have those checked and replaced if necessary.