In a large bowl, mix banana ketchup, Sprite, soy sauce, vinegar, oyster sauce, chili oil, brown sugar, black pepper, and minced garlic to make the marinade. Stir until you see the sugar starting to dissolve.
Add the pork cubes to the marinade. Use your hands or a big spoon to get every piece coated. Cover the bowl, then place it in the fridge for at least 2 hours or overnight.
Preheat your grill to medium-high heat. Thread marinated pork cubes onto skewers, not too tight to ensure even cooking.
Place the skewers on the grill, turning every few minutes. Cook for about 15-20 minutes until the pork is cooked through.
To use a pressure cooker, place the skewers with some marinade. Set to high pressure, cook for 15 minutes, then let natural release.
After release, remove skewers and brush with banana ketchup, oyster sauce, and sesame oil mix. Grill or broil for a glazed finish.
Notes
For best results, allow the pork to marinate overnight and ensure proper sealing of your pressure cooker for even cooking.