My 2004 kia optima idels hard when at a complete stop even without the ac on. whats wrong?

What were you doing when everything quit? Jump Start your Car?

When the oil lamp lights, it means that your oil pump is not giving the right pressure or it is not working, If it only happens during idling, it indicates that the pump is about to wear and needs servicing, If its intermittent, it may just be a loose wire connection to the sender or a defective sending unit. Try to replace first the oil pressure sending unit.

problem could be in the switch if fan control speeds off.

If you were driving and your Kia Optima just turned off. Your timimg belt broke and you will also need a crank shaft sensor too. There is a total of two belts inside the motor area (timing belt and balance belt) I would change out the ac and power steering belt as well so their is a total of four belts on the KIA 2004 OPTIMA.

CHECK AC COMPRESSOR CLUTCH FUSE AND RELAY.MAKE SURE POWER IS GOING TO COMPRESSOR CONNECTOR.IF NO CHECK FUSE AND RELAY.IF YES.YOUR PROBLEM COULD BE AC CONTROL SWITCH BAD OR BLOWER MOTOR.COMPRESSOR CLUTCH SHORTED OR OPEN.AC PRESSURE SENSOR BAD OR REFRIGERANT IS LOW.

there's a bad switch somehwere inside the dash. What does the dealer say?

if you can some how manage to get it opened, spray some lubracant on the button inside the door. if not you'll need to replace the release cable.

Try the ignition switch,

For the Crank sensor there is a small metal disc that mounts behind the sensor if that is cracked or dammaged or installed backwards you will get same results as if it wasn't Make sure the timing marks line up on your timing belt. www.kiatechinfo.com

look for tie and clean batetrie conectors and have your batetrie take to an autozone for a free test they will do it with the batterie still in car

This could be multiple issues.
1.) timing belt
2.) Crank sensor
3.) Fuel pump (although usually they do not just die they get weak)

Check these let me know.