Like Tim I have read a bit about Ultra Low Sulfur Diesel (ULSD) on the internet. Below is a web site address. It includes an article written in Aug 2007 that gives a good overview of what ULSD is and why the use of additives are advisable. The site includes the results of tests done to determine the effectiveness of additives. They not only tested legally registered additives but two stroke oil and used engine oil as well. Now why the heck would they be testing them? (BTW, two stroke engine oil scored better than the additive I buy from GM. That's another weird thing, GM dealers sell diesel additive, they just won't officially recommend you use it in their vehicles). http://inchoate.harm.org/~halbritt/dodge/Diesel%20Fuel%20Additive%20V3.pdf Ted **************************************************** * General Information About BEE-L is available at: * * http://www.honeybeeworld.com/bee-l/default.htm * ****************************************************