Mix together spice mixture
Put pork roast into a sealable bag, and pour in soy sauce, half the can of Dr. Pepper, and half the spice rub.
Marinade in the fridge for 4-16 hours
Put roast, and marinade in slow cooker on low heat add in salsa. onion, green chilies and 1/2 a cup of brown sugar
Cook 7 hours.
Drain the excess liquid out of the slow cooker, shred the pork, and return it to slow cooker.
Pour in enchilada sauce, sriracha, the other half of the brown sugar, Dr.Pepper, and spice mixture, and stir to coat.
Cook two additional hours, and enjoy in tacos, burritos, enchiladas, in salads, or over rice