I've been using the following marinade for Barbecued Pork Tenderloin for a good number of years. The recipe came from either The Vancouver Sun or Province newspaper - I can't remember which. But it's definitely a keeper.

Barbecued Pork Tenderloin
1/4 cup soy sauce (I prefer to use Tamari)
2 tablespoons sherry
2 tablespoons vegetable oil (I use safflower oil)
1 tablespoon brown sugar
1 tablespoon grated fresh ginger
1 teaspoon honey
1 garlic clove, crushed
1 pork tenderloin, about 1 pound

Combine all ingredients except pork tenderloin in a small bowl; stir to mix well. Pour marinade in a Ziploc bag and add pork tenderloin; seal bag. Let pork marinate for 10 minutes (or longer).

Remove pork from bag; reserve marinade. Place pork on greased barbecue grill over medium-high heat. Close lid and cook for about 12 to 15 minutes or until pork is cooked, turning once and basting frequently. Slice and serve.