A fuel additive composition, fuel composition, method of improving the injector performance of a fuel injected engine, method for preventing or cleaning up deposits in an engine or fuel system, method of reducing wear in a fuel system of an engine, and method of improving the demulsibility of a fuel composition. The fuel composition includes from about 5 to about 300 ppm by weight based on a total weight of the fuel composition of a hydrocarbyl soluble quaternary ammonium carboxylate derived from a quaternary ammonium carbonate and an organic acid.