Combine Coke and 1/4 c. brown sugar. Place pork roast in a ziploc bag and pour the Coke and brown sugar mixture over it. Allow to marinate for at least 3 hours. (Over night is best!)
Remove roast from plastic bag and place in the crock pot. Pour the marinade in the crock pot and sprinkle salt over the roast. Place the lid on the crock pot and cook on high 3 1/2 – 4 hours.
In a blender, combine enchilada sauce, minced garlic, green chillies, and 3/4 c. brown sugar; set aside.
Remove roast from crock pot and shred; discard of liquid. Place shredded pork back in the crock pot and add enchilada sauce mixture. Stir around to mix the meat with the liquid and cook for 30 more minutes, covered. Add more salt if more flavor is needed.