2005 Nissan Titan Owner's Manual - Page 304

Octane rating tips Using unleaded gasoline with an octane rating lower than recommended can cause persistent, heavy "spark knock." ("Spark knock" is a metallic rapping noise.) If severe, this can lead to engine damage. If you detect a persistent heavy spark knock even when using gasoline of the stated octane rating, or if you hear steady spark knock while holding a steady speed on level roads, have a NISSAN dealer correct the condition. Failure to correct the condition is misuse of the vehicle, for which NISSAN is not responsible. Incorrect ignition timing may result in spark knock, after-run and/or overheating, which may cause excessive fuel consumption or engine damage. If any of the above symptoms are encountered, have your vehicle checked at a NISSAN dealer. However, now and then you may notice light spark knock for a short time while accelerating or driving up hills. This is not a cause for concern, because you get the greatest fuel benefit when there is light spark knock for a short time under heavy engine load. FLEXIBLE FUEL VEHICLE (FFV) FUEL RECOMMENDATION (if so equipped) Your vehicle is designed to use (E-85) Fuel Ethanol, "Regular" unleaded regular gasoline or any percentage of the two fuels combined. U.S. government regulations require Fuel Ethanol dispensing pumps to have a small, square, orange and black label with the common abbreviation or the appropriate percentage for that region. Ethanol Fuel (E-85) E-85 is a mixture of approximately 85% fuel ethanol and 15% unleaded gasoline. WARNING ● Ethanol vapors are extremely flammable and could cause serious personal injury. ● Never have any smoking materials lit in or near the vehicle when removing the fuel filler cap or filling the tank. ● Do not use E-85 as a cleaning agent and never use it near an open flame. Fuel requirements Your vehicle will operate on both unleaded regular gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number (Research octane number 91), or E-85 fuel, or any mixture of these two. For the best starting and vehicle driveability results, do not continually switch between E-85 and unleaded regular gasoline. If you must switch fuels, NISSAN recommends the following: ● do not switch when the fuel gauge indicates less than 1/4 full ● add more than 5 gallons of fuel CAUTION Use of other fuels such as Fuel Methanol may cause powertrain damage or a loss of vehicle performance. General information This information is for Flexible Fuel vehicles (FFV) only. FFV vehicles can be identified by the fuel filler door label that states Ethanol (E-85) or Unleaded Gasoline Only. This section only covers those subjects that are unique to Flexible Fuel vehicles. CAUTION Only vehicles with the E-85 filler door label can operate on E-85. Fuel system or other damage can occur if E-85 is used in vehicles that are not designed to run on E-85. 9-4 Technical and consumer information