The ever changing quality of Number 2 diesel fuel presents the end user (fleet, owner operator, consumer, etc.) with a nearly insurmountable challenge. With no governing body to set and enforce fuel specifications, the user is supplied fuels that vary greatly from supplier to supplier and from region to region. These fuels vary greatly in their combustion quality, winter operability and water carrying capability. The subjects covered in this “Fuel Quality Improvement” paper are to assist the user with guide lines for improving equipment dependability and reducing operating costs per hour/mile.The area of “Fuel Quality Improvement” is to say the least dealing with a moving target. Between now and the end of the 20th century, the industry will continue dealing with major changes in fuels and engine technology. This paper deals with our monitoring of fuel quality over the past four years and necessary treatment to solve fuel related problems.