1997 Ford F350 Owner Guide 1st Printing - Page 294

NOTE: If you replace your fuel cap with an aftermarket fuel filler cap, the customer warranty may be void for any damage to the fuel tank and/or fuel system. RWARNING The fuel system may be under pressure. If the fuel cap is venting vapor or if you hear a hissing sound, wait until it stops before completely removing the cap. A venting fuel tank is not an abnormal condition. It may be caused by: u Too volatile a fuel for the weather conditions. The service stations sometimes sell winter grade fuel in the summer. altitudes. u Pulling a heavy load on hot days, or at high u Extended periods of idling with the engine periods on extremely hot days. RPM increased above the normal idle range. u Parking vehicle in full sunlight for extended Choosing the Right Fuel NOTE: Read the 7.3L Diesel Engine Owner Guide Supplement for information regarding correct fuel requirements for your diesel-powered vehicle. Use only UNLEADED FUEL. Using leaded fuel is prohibited by federal law and could damage your vehicle. The damage may not be covered by your warranty. Your vehicle was not designed to use fuel containing manganese-based additives such as MMT. Additionally, vehicles certified to California emission standards (indicated on the 295