Pull the membrane off the underside of the ribs. Cut each rack in half.
Make the rib seasoning by mixing together the brown sugar, chili powder, salt, garlic powder, cumin, black pepper and cayenne pepper.
Rub the seasoning mix all over the ribs and place them inside the pressure cooker pot, standing up, horizontally side by side.
Pour in the pop, worcestershire sauce, hot sauce and 1/4 cup of the BBQ sauce.
Lock the lid on the pressure cooker and close the vent. Set the pressure cooker to high pressure and cook for 25 minutes. After the cook cycle, let the pressure release naturally.
Preheat the oven to 400F.
Place ribs on a baking sheet lined with parchment paper. Brush the remaining 1/2 cup of BBQ sauce on the ribs.