Wash Pork Tenderloin and place in a one gallon zip lock bag or container. Pour the entire bottle of Kraft Italian Dressing in as a marinade. Place in the refrigerator for a minimum of two hours and not more than eight hours. Place on gas grill over medium low heat. Roll over about every fifteen minutes. Be sure to place the larger section of the tenderloin in the middle of the grill and the smaller end toward the outside. This will help even out the cooking. Grilling time is usually about 1 hour or until the middle of the tenderloin reaches a temperature of 175 degrees.