I have run several major R&D labs and seen a lot of additives. We even tested samples from auto parts stores to see if they did as claimed.Most additives fail every reasonable test that we subject them too. I was a skeptic until a client brought us a formulation to make and test. This material is called MG22D and it is sold by Freedom Additives. We have run it is Cats, IH,Cummins,Mercedes and Detroit deisels engines and so far it has done well. Mileage increases are in the 8% to 35% range and emmissions reductions are about the same%. The additive has a cetane improver, a cold flow improver and a detergency additive. Yes,I know you have heard it before, but believe me I am the biggest skeptic I know. Check it out at the Freedom Additive web site.