is it a single car, or in a group? if it is in a group, check to see if the communication LED on the swing panel for the car you are having trouble with is going out intermittently. If the led goes out, and the car is not communicating to the group, it will start going into a wild car type mode, where it will automatically register car calls and stop at those floors, and continue until the communication is re-established. worth a shot, i had a bad ribbon cable from the comm port board to the swing panel in the car, and the group comm led was out, it would just register random calls until i replaced the cable. just another idea. good luck