i drive my car down the street and all of sudden the car would just stop. i don't know whats causing it.. i know its not the battery since the radio stays on so i'm guessing its a motor problem?

 

To diagnose we need more info, like when, how long its been operating, spark?, fuel?, etc. I know a big problem has been a main relay behind the dash. Search for info on that and see if it matches what's been happening to you. BTW, the radio will be on so long as your key is turned to the ON position.