Mix together some garlic power, onion powder, salt and pepper and rub it on your pork butt.

In your slow cooker, place your pork and onion pieces inside.  Pour your soda on top of everything and cover and cook on high at least 6 hours.

Remove the lid after 8 to 10 hours and the meat should be falling a part at the touch of your fork.  Remove the meat from the slow cooker into a bowl and then drain your slow cooker of the onions and liquid.  Add your meat back to the slow cooker and shred it up with two forks.  Stir in as much of your BBQ sauce as you like.  At this point, you can serve immediately or you can turn the slow cooker to the “keep warm” setting and let it stay warm up to 4 or 5 hours until you’re ready to eat.