Place tenderloins in a 9x11-inch casserole dish.

Mix together vinegar, mustard, honey, olive oil, garlic, salt and pepper. Pour over the tenderloins, cover and refrigerate at least 8 hours, turning at least once during this time.

Cook the pork on medium-high directly on the barbecue grill, with the lid closed. Turn occasionally. The meat is done when the juices run clear, approximately 25 minutes.  Remove from barbecue and check internal temperature. It should be at least 145°F. Cook longer if the tenderloins are extra thick.

Transfer the tenderloin to a plate and tent with foil for 5 minutes.  

Cut into 1-inch pieces and serve.