Hate to say it, tried it all. Seafoam, and every other additive made, I mean every single one, they all failed in spades. My injectors were replaced once at 90 k for bad smoke at idle. Smoked very badly at idle again at 185 k. I was not ever convinced my injectors needed replacement again, simply because after a road trip the smoking went away for about a week. I had an epiphany, it is my usage causing the injectors to foul. I took a 1500k road trip with a three horse trailer loaded with 5000lb of horses. I did not go easy on my truck in the mountains. What I did was put a quart of walmart tranny fluid in each tank, high detergent I heard might help. That was two months ago, no smoke folks. I keep the truck in tow haul mode, and drive it like a truck, I drive it hard, I use it hard, it gets hot. I think the issue is using this particular series as a car, not a truck. It was never intended to be coddled. It was the first series, and made to be used hot. My balance rate is now text book perfect, my truck runs perfectly now at 210 k. Truck is bone stock. Try it.