Abstract: A system for equalizing the performance among the cylinders of an internal combustion engine which involves the introduction of increased fuel to under-performing cylinders, and reduced fuel to over-performing cylinders, with the result that the cylinders all perform at a more uniform level. In the first embodiment, this is achieved by means of selecting unit injectors for a diesel engine according to the cranking compression in each cylinder so that cylinders with lower compression receive more fuel. In the second embodiment, in which injectors in either diesel or gasoline engines are controlled by an electronic controller, temperature sensors within the individual cylinders report to the electrical control unit which then operates the injectors to meter the fuel injection such that hotter operating cylinders receive less fuel and cooler cylinders receive more. The engine is then tuned according to the engine manufacturer's standard procedures.