Salt and pepper pork roast on both sides. Put in the slow cooker with about a cup or so of water. Cook on low for 8 hours or overnight.
The next morning, drain out all of the water and remove as much fat (or bone if you have one) as you can from the pork. Shred with two forks.
Mix root beer, tomato sauce, honey, garlic, brown sugar, salt, pepper, and cumin.
Pour sauce over pork and cook on LOW for another 3 to 4 hours.
Heat tortillas in a 350-degree oven. Add some shredded cheese and melt. Add pork, cilantro, and sour cream. I like a squeeze of lime on mine to freshen it up.