Why is my car misfiring after driving it all day which was running great. on 2004 Hyundai Accent

I shut the car off went in for about 10 minutes came out started the car and it just started misfiring the check engine light came on flashing and is running really rough what could the problem be?

Asked by for the 2004 Hyundai Accent
check the plugs, wires and coil.