Fuel Specific Gravity Testing
WARNING: This page is about a different car, the 2005 GMC Sierra, 2005 GMC Cab & Chassis Sierra, 2005 Chevrolet Silverado, and 2005 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Use a J 38641-B Diesel Fuel Quality Tester to measure the fuel specific gravity (API Rating). See Special Tools . Follow the instructions on the tool to obtain the proper temerpature-adjusted value. This information must be accurate for the proper diagnosis of the fuel system.