Combine all the ingredients except the tri tip in a small bowl. Stir to combine. Place the tri tip in a zip top bag and pour the marinade over the tri tip, massaging the bag so that the tri tip is well coated in the marinade.
Place the trip tip in the refrigerator and allow it to marinate for at least 6 hours. If possible, flip the bag periodically so that the tri tip is evenly coated in the marinade.
Heat the Traeger to 375 F, per standard instructions, or heat a regular grill to medium heat. Grill the tri tip until it has reached desired donenes. For rare, cook the tri tip until it has reached an internal temperature of 120 F. This will take about 25 minutes.
Remove the tri tip from the grill and allow it to rest for 10 minutes before serving. Slice thinly and serve hot.
Recipe by The Little Chef at http://littlechefblog.com/six-hour-marinated-tri-tip/