Bill it may be worth trying fuel from different refineries. Even with the old fuel there are certain brands I stay away from as they seem to go through the engine like mouthwash. As fate would have it the best consistant milage on the old fuel was obtained by a brand that generally has a reputation of problems with their gas. But their diesel is good. Up to 20 percent or so apparent milage drop was observed with one other brand. Irving fuel only available in north east quadrant of states was the good brand by the way. I do not know if that fuel is coming out of the canadian refinery for the american stations or not though. I wonder if the heavy truckers have already established the brands that are better. Must ask some truck drivers I know the next time I see them. If experiences with all brands are simular we might have to use biodiesel as was mentioned to get some semblance of milage back. I think your experiences so far will probably be common unfortunatly. At least with certain engines if not all. But hope not. Any injection pump leaks yet? I really hope that is not going to become a real problem with everyone as well. Some reports have indicated it might. I would also have preffered to see ravings of excess milage on the new fuel but life does not seem to work like that usually.