1 (6 ounce) can frozen lemonade concentrate, thawed
3/4 cup barbecue sauce
Place pork in a Dutch oven and add enough water to cover. Heat to boiling; reduce heat to low. Cover and simmer about 1 1/2 hours or until tender.
Remove pork to a 13 x 9-inch baking dish. Mix lemonade concentrate and barbecue sauce. Pour over pork; turn meat to coat with marinade. Cover and refrigerate, turning pork occasionally, at least 4 hours but no longer than 24 hours.
Brush grill rack with vegetable oil. Heat coals or gas grill for direct heat.
Remove pork from marinade. Heat reserved marinade to a boil; boil 2 minutes.
Grill pork, meaty sides up, uncovered, 4 inches from medium-hot heat about 30 minutes, turning and brushing frequently with heated marinade, until glazed and heated through. Discard any remaining marinade.