Why does car come to s halt while still driving it on 2004 Kia Optima

Runs and starts fine after driving for awhile it slows down till it comes to a halt. After letting it cool down it will run normal for another while. Had the transmission oil changed still the same what can it be

Asked by for the 2004 Kia Optima
Have it scanned for codes, if engine is stalling, possible crankshaft position sensor.
It doesnt stall motor keeps running but comes to a halt and wont roll no more till it completly cools down