In bowl, combine ketchup, brown sugar, vinegar, worcestershire sauce, mustard and onions. Set aside. In small bowl, combine garlic powder, salt and pepper.
Rub garlic powder mix over ribs. In lg skillet, over high heat, brown ribs on both sides in oil. Place ribs in slow-cooker. Pour sauce over ribs. Cover, cook about 6 hrs, or until meat is falling off the bones. Serve ribs w/ sauce.