Air/vaporin diesel fuel is a common problem with any diesel vehicle where the fuel tankis located at a lower point than the engine. The movement of the fuel insidethe tank, and the process of fuel transfer under these conditions creates asmuch as 10% air/vapor within the fuel. Symptoms of air/vapor can be low horsepower,poor fuel mileage, excessive smoke, injector failure, hard starting, surgingand rough running. You can eliminate this problem with a FASS Fuel Air SeparationSystem and get "test cell" performance under real world conditions.