BBQ Pork Sandwiches

2 pounds boneless pork loin
1 onion, chopped
3/4 cup cola beverage
3/4 cup barbecue sauce
8 sandwich buns

Combine pork loin, onion, cola, and barbecue sauce in a slow cooker; cook, covered, on high for 5 to 6 hours until very tender. Drain and slice or shred pork, and then serve on buns with additional barbecue sauce, if desired.