Salt and pepper top and bottom of the pork shoulder.
Place onion slices in the bottom of large crock pot. Place pork shoulder, fat side down on top of onions. Put garlic cloves over top of the pork shoulder.
Pour can of peppers, Dr. Pepper, and and brown sugar on top of the pork and garlic.
Cook on low for 8 hours.
Shred with fork or salad choppers and keep warm till ready to serve.
Notes
Leftover freeze great or can be used in the enchiladas or burritos.