Improved gasoline compositions containing a minor amount of a polyalphaolefin having a viscosity at 100.degree. C. from 2 to 20 centistokes, and optionally also an aliphatic polyamine, an alkali or alkaline earth metal salt of a succinic acid derivative, and/or a polyolefin; together with a concentrate for the production of such gasoline composition and a method of operating a spark-ignition engine using such gasoline composition.