Preheat a grill to medium-high. Remove the ribs and cola from the roasting pan, clean the pan, and fill it up again with the remaining cola.
Preheat the oven to 325 degrees F.
Once your grill is nice and hot, lay the ribs on the grill and begin cooking. Every time you turn the ribs over on the grill, put them back in the roasting pan filled with cola and then back onto the grill. Repeat this process before each turn in order to build a layer of sugar on the ribs.
After the ribs are almost finished cooking, about 30 to 35 minutes, take the ribs off the grill. Fill a new roasting pan with your favorite barbecue sauce. When the ribs are cool enough to handle, cut the ribs into individual portions, and put them into the roasting pan with the barbecue sauce. Bake the ribs in the oven for 1 hour, or until the meat is falling off the bone.