A comprehensive testing program was initiated to evaluate the performance characteristics of gasoline additive packages representing various types of chemistry. The additives were evaluated in a standard reference gasoline meeting ASTM D 439 requirements. Port fuel injector keep-clean and clean-up tests utilized dynamometer operated vehicles. Intake valve deposit control tests utilized stationary single-cylinder and four-cylinder carbureted engines. Carburetor detergency tests were conducted on a stationary six cylinder engine. Fuel injector dirty-up repeatability varied significantly. Intake valve deposit control tests and carburetor detergency tests showed acceptable repeatability. Performance of the additives varied widely.