1997 Ford Ranger Owner Guide 1st Printing - Page 290

A venting fuel tank is not an abnormal condition. It may be caused by: s Too volatile a fuel for the weather conditions. The service stations sometimes sell winter grade fuel in the spring. s Pulling a heavy load on hot days, or at high altitudes. s Extended periods of idling with the engine RPM increased above the normal idle range. s Parking vehicle in full sunlight for extended periods on extremely hot days. Choosing the Right Fuel Use only UNLEADED FUEL. The use of leaded fuel is prohibited by 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 underhood Vehicle Emissions Control Information label) are designed to operate on California reformulated gasolines. If California reformulated gasoline is not available when you refuel, your vehicle can be operated on non-California fuels. However, even though your engine will perform adequately on other gasolines, the performance of the emission control devices and systems may be adversely affected. Repair of damage caused by using a fuel that your vehicle was not designed for may not be covered by your warranty. Octane Recommendations Your vehicle is designed to use regular gasoline with an (R+M)/2 octane rating of 87. We do not recommend gasolines labeled as "regular" in high altitude areas that are sold with octane ratings of 86 or even less. 290