For those that are interested, here is an update...
Using Temple University's technology, "Popular Science (February, 2009 page 34) reports that a California company (Save The World Air, Inc -
http://www.stwa.com/) has built such a device for 'big rigs' using electric fields to reduce this fuel's viscosity. Fuel economy improved as much as 10% in these large trucks. The article also indicates that, if all goes to plan, a smaller version will be available for diesel cars by 2011.