A variety of fuel tolerance tests were conducted utilizing Ford's PROCO engine, a direct fuel injection stratified charge engine developed for light duty vehicles. These engine tests were run on the dynamometer and in vehicles. Data indicate an 89 RON octane requirement, relatively low sensitivity to volatility characteristics and good fuel economy, emission control and operability on a certain range of petroleum fuel and alcohol mixes including 100% methanol. Fuels such as JP-4 and Diesel fuel are not at present suitable for this engine. There were no engine modifications tested that might improve the match between the engine and a particular fuel. The 100% methanol test was conducted with a modified fuel injection pump. Durability aspects including compatibility of various fuels with the materials in the fuel system were not addressed.