STARTED THE VEHICLE ON LEVEL GROUND, VEHICLE WAS IN PARK, EMERGENCY BRAKE WAS NOT ON, FORGOT SOMETHING IN HOME, GOT OUT OF VEHICLE & PROCEED TOWARDS HOME BUT BEFORE I GOT THERE BACKED UP & HIT HOME, ENGINE THEN STALLED, RESTARTED ENGINE & MOVED VEHICLE BACK TO ORIGINAL POSITION, I THEN TRIED TO REPLICATE EVENTS, VEHICLE DID NOT MOVE, PUT VEHICLE IN PARK, VEHICLE REMAINED STATIONARY, PUT VEHICLE IN REVERSE & VEHICLE IMMEDIATELY BEGAN TO MOVE. MY WIFE WAS IN THE VEHICLE & REPORTED THAT VEHICLE DID NOT MOVE UNTIL I WAS COMPLETELY OUT OF VEHICLE & PROCEEDING TO HOME WITH MY BACK TURNED.