In small saucepan, combine barbecue sauce, coffee, tomato paste, thyme, cumin, red pepper flakes, salt, and pepper. Cook over medium heat for about 5 minutes. Remove and cool. Pour half into shallow bowl or resealable plastic bag, and reserve remaining half. Add tenderloin to bowl or bag and rotate in sauce to evenly coat. Tightly seal and marinate at room temperature for a minimum of 30 minutes.