Make sure the Pork Rub is well pulverized. Large chunks of herbs can become stuck in the injector. Grind them down further in a mortar and pestle or spice grinder.
Combine all the ingredients for the pork injection marinade in a medium bowl. Let it stand for 10 minutes, and whisk a few times before using.
Fill the syringe with marinade, and inject it into multiple parts of the pork roast. See my video below for injection technique.
Carefully wrap the pork roast in plastic wrap, and place it in the refrigerator for 1-4 hours.
Season and cook the pork roast as directed.
Discard any leftover marinade that has come into contact with raw meat.
Make this marinade up to 3 days in advance, and store in the fridge in an airtight container.