WHILE TURNING RIGHT TO PARK IN A RESIDENTIAL TOWNHOUSE PARKING SPACE, THE CAR ACCELERATED SUDDENLY AND HIT A TREE WHICH WAS VERY CLOSE BUT AT THE TOP OF A SLANTING HILL. IT FELT LIKE THE CAR WAS SLIPPING ON ICE BUT THERE WAS NO ICE. A PERSON OUTSIDE OF THE CAR HEARD A STRANGE NOISE. IT FELT LIKE THERE WAS NO ABILITY TO CONTROL THE CAR. I TRIED TO BACK UP, I FELT THE SAME SLIPPING SO I STOPPED AND LEFT THE CAR. THE SAME PERSON HEARD THE NOISE AGAIN WHEN I WAS BACKING UP. I AM AN EXPERIENCED DRIVER WITH A CLEAN DRIVING RECORD FOR OVER 20 YEARS AND HAVE NEVER EXPERIENCED THIS. IT WAS SUNDAY AFTERNOON AND THERE WERE NO WEATHER RELATED ISSUES. THIS WAS THE 3RD STOP OF THE DAY OVER A 1-2 HOUR PERIOD. THIS IS A QUIET STREET SO THERE WERE NO TRAFFIC ISSUES. THE CAR WAS LEAKING OIL SO IT WAS TOWED TO THE BODY SHOP. *TR