:Ford Motor Company has introduced its dedicated Natural Gas Vehicle (NGV) trucks as mid-year 1997 offerings to complement its dedicated Crown Victoria and bi-fuel Qualified Vehicle Modifier (QVM) product line-up. The 5.4L F-250 full-size pick-up truck and the 5.4L E-250/E-350 full-size vans are production vehicles maintaining Original Equipment Manufacturer (OEM) quality and warranty while complying with all applicable corporate, federal and state requirements. Both trucks are the first OEM vehicles to certify at the Super Ultra Low Emission Vehicle (SULEV) California medium-duty vehicle standard, the Federal Ultra Low Emission Vehicle (ULEV) standard, and the Federal Inherently Low Emission Vehicle (ILEV) emission standard. The use of natural gas (NG) as a vehicle fuel required unique hardware changes in the areas of fuel storage, fuel metering, and the emission control system. Unique approaches in calibration technique were also employed to optimize vehicle driveability, performance, and emissions. Changes were required to the strategy in the areas of injector timing, fuel control, spark advance, and exhaust gas recirculation (EGR). A conditioning catalyst emission control technique was selected and its durability was proven for production. Deterioration factors (DF) were generated from actual 193,000 km (120,000 mile) durability testing and were accepted for certification. Performance and driveability were shown to be comparable to the equivalent gasoline vehicles.NOTE: All units are reported in SI except regulatory emission based data and standards.