Prepare medium-hot banked fire in covered kettle-style grill. Place pork over indirect heat, cover grill and grill for 1 1/2-2 hours, until internal temperature, measured with a meat thermometer, registers 150-155 degrees F. Meanwhile, for sauce, in a small bowl combine chili sauce, vinegar, lemon juice, mustard and garlic; mix well. Brush pork frequently with sauce during the last hour of grilling time. Let pork rest for 10 minutes before slicing to serve.