Use of a gasoline fuel composition comprising (a) a major portion of gasoline blending components (b) from 0 vol % to 25 vol % of oxygenated hydrocarbon and (c) from 0.01 vol % to 5 vol % of a diene compound for the purpose of increasing the injection duration at the end of a 48 hour deposit formation phase in a direct injection spark ignition engine by at least 10%.