How does Sea Foam High Mileage work? [SOLVED]

Thanks for the question John. Both products are similar and both products are strong. The difference is that High Mileage is formulated to keep a truck like your GMC running better over a longer engine life. In fuel it will work to clean your Yukon’s fuel injectors and upper engine areas. If used regularly in oil will reverse old oil residue and buildup that can cause oil burning and affect oil flow. Considering your truck has a Gasoline Direct Engine (fuel injectors inside the chambers), consider a few Sea Foam Spray upper engine treatments per year to help keep your intake valves clean. Hope this helps!