Spray the bottom of a crock pot with cooking spray.
Place Pork Roast at the bottom of the crock pot. Next place onion slices all around the pork. Next empty two cans of Pepsi (or Coca Cola) on top of the pork. Sprinkle pork liberally with salt and pepper. Place lid on the crock pot and set temperature to low and cook for 8 hrs.
After 8 hrs remove lid for 1/2 an hour, then remove roast from crock pot, place on plate or in a bowl and with two forks shred it to desired consistency and enjoy!