1996 Ford Bronco Owner's Manual - Page 280

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 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 Use only UNLEADED FUEL in your vehicle. Using leaded fuel is prohibited by federal law. Your warranty may not apply if your vehicle is damaged because you used the wrong fuel. Vehicle inspection programs may detect misfueling. Under these circumstances, you may be required by law to make costly repairs at your own expense. 283