- Slice tenderloins lengthwise almost in half, being careful not to cut all the way through; press open to flatten. Carefully place pork in large plastic food storage bag.
- Combine 3/4 cup roasted garlic teriyaki sauce, rice vinegar and onion powder; pour over pork. Press air out of bag; close top securely. Turn bag over several times to coat pork well. Let stand 30 minutes, turning bag over occasionally.
- Remove pork from marinade; discard marinade.
- Cook pork on grill 4 to 5 inches from medium-hot coals 10 to 12 minutes, or until meat thermometer inserted into thickest part registers 160ºF., turning over and brushing occasionally with remaining 2 Tbsp. roasted garlic teriyaki sauce.
- Let stand 5 minutes before slicing.