A method and apparatus for providing automatic pressure balancing of an internal combustion engine. The engine includes cylinders, fuel injector valves provided to selectively deliver fuel directly into the cylinders, fuel-balancing valves each fluidly connected to the fuel injector valves for controlling the fuel delivered to the fuel injector valves and cylinder pressure sensors each mounted to one of the cylinders. The method comprises an automatic pressure balancing procedure including the steps of monitoring a cylinder pressure in each of the cylinders, determining a peak combustion pressure produced in each of the cylinders, calculating a mean peak pressure produced in all of the cylinders, calculating a pressure difference between the mean and the peak pressure and incrementally adjusting the fuel delivered by one of the fuel-balancing valves to the corresponding fuel injector valve mounted to the cylinder having the pressure difference larger than a predetermined pressure value.