This Preliminary Information communication provides information to the technician on how to diagnose and repair vehicles that may have an engine that misfires, possibly coming to a stop or on acceleration. This may be caused by contaminated fuel. Technician will need to inspect the inside of the fuel rail and fuel tank for signs of fuel contamination. If fuel contamination is present, refer to the "Fuel System Cleaning" procedure in Service Information and clean the inside of the fuel tank, fuel lines and fuel rail. Also the fuel injectors will need to be cleaned by following "Fuel Injector Cleaning Procedure" in Service Information. Technician may report a repeat misfire concerns on these cylinders caused by sticking valves after cleaning the fuel system. If the valves are sticking do not replace the cylinder head or valves until first attempting to clean them. This should be done by using the cleaning procedures listed in the latest version of PIP5029.