GM-GMC: fuel mileage, duramax diesel, gmc 3500

Question
Is ther a reasonable way to increase fuel mileage without getting into a lot of expense, on a 2004 GMC 3500 crewcab dually equiped with the Duramax diesel and Allison 5-speed automatic transmission. The engine is still under factory 5-year, 100,000 mile warranty.Currently has 16,000 miles on odometer?

Answer
Larry unfortunatley no there is nothing you can do about this with out spending money the cheapest option is a bullydog computer it is plug ang play devise I have heard of as much as 5 mpg or more with these oryou can do a turbo but this will void the waranty thanks Mark