An ignition system for an internal combustion engine includes a prechamber ignition device, a fuel admission valve for the prechamber ignition device, and a combustion consistency control mechanism configured to receive data indicative of at least one of a magnitude of a peak pressure in a combustion prechamber of the prechamber ignition device or a timing of the peak pressure in the combustion prechamber. The combustion consistency control mechanism calculates an error based on the data, and outputs a valve opening command to a fuel valve to produce a shot of combustion-initiating gases from the prechamber device, the valve opening command being based on the error.