Grilled Pork Tenderloin With Easy Marinade

Name: Grilled Pork Tenderloin With Easy Marinade
Ingredients: ¼ cup mild-flavored (light) molasses; 3 Tbsp. apple cider vinegar, divided; 2 Tbsp. Dijon mustard; 2 Tbsp. coarse-grained mustard; 1 ¾-pound pork tenderloin, silver skin removed; Vegetable oil (for grill); Kosher salt and freshly ground black pepper