Stir the pork, 1/4 cup vinegar, Italian seasoning blend, lemon juice, salt, and red pepper flakes in a large bowl until the meat is coated in the marinade. Cover and refrigerate for 1 hour (but no more because of the vinegar), stirring once or twice.
Take the bowl with the pork out of the fridge and set it on the counter for 20 minutes. Meanwhile, pour the broth and liquid smoke into the insert set in a 5-, 6, or 8-quart Instant Pot. Put a pressure- and food-safe rack or trivet in the insert.
Thread the pork cubes onto eight 6-inch bamboo skewers, 4 or 5 pieces per skewer. Pile the skewers onto the rack and lock the lid on the pot.
If you have the MAX model: Set your Instant Pot to MAX and set time for 12 minutes.
When the pot has finished cooking, use the quick-release method to bring the pressure back to normal. Unlatch the lid and open the cooker. Cool right in the pot for a few minutes. Meanwhile, whisk the mayonnaise, black pepper, and remaining 3 tbsp vinegar in a small bowl until uniform.
Pull the pork pieces off the skewers and line them in the toasted hoagie rolls or buns. Top with the mayonnaise sauce to serve.
Notes
Other Pots • For a 3-quart Instant Pot, you must halve almost all of the ingredient amounts except you must use 1 cup chicken broth (with 1 tablespoon liquid smoke) in the insert. • For a 10-quart Instant Pot, you must use 21/2 cups broth and 3 tablespoons liquid smoke in the insert while otherwise completing the recipe as stated.
Beyond • Add chopped lettuce (particularly iceberg lettuce), chopped tomatoes, and/or sprouts (particularly radish sprouts) to the hoagies with the pork. • If you’ve used a 6- or 8-quart Instant Pot, you can crunch the meat as it would be on a grill. Remove the skewers as directed in step 6, then remove the rack from the (hot!) insert, pour out any liquid in it, and wipe it out. Return it to the pot and set the air-frying basket attachment in the insert. Setthe Instant Pot Air Fryer Lid over the pot and air-fry at 400°F for 5 minutes, rearranging the skewers once to allow even browning. • Alternatively, set the cooked skewers in a nonstick grill pan set over medium-high heat or on a grill grate over high heat. Grill for about 2 minutes, turning several times, until browned.