In a small bowl, combine the onion powder, garlic powder, salt, pepper, paprika, allspice, celery salt, cloves, and mustard powder. Mix well. Rub the spice mixture all over your pork. Add the water to a large crock pot. Place the spice rubbed pork in the pot and cover. Cook on high for four hours, or until tender and falling apart. Remove the meat from the crock pot, leaving the juices behind. Shred the meat with clean hands, or use two forks to "pull" it apart.
For the sauce:
Skim the solids and visible fat from the top of the liquid and discard. Add all of the sauce ingredients to the remaining liquid in the crockpot, whisking until smooth. Cover and cook on high for about 10 minutes or until slightly thickened. Add the meat back to the sauce and stir until fully coated. Serve hot.