To counter-act the effect of using low-sulfur fuel in my 2005 LLY, I add a 50/50 mix of TCW3 2-stroke outboard motor oil and Diesel Kleen to the tank every time I fuel up. I use 2/3 ounces of the 50/50 mix per gallon. So far, so good with 82,000 miles on the clock.
As documented elsewhere on...