The invention relates to an engine having at least two combustion chambers, a shared high-pressure fuel storage tank for holding fuel gas available as pressurized gas, and means for direct injection of the fuel gas from the high-pressure fuel storage tank into the combustion chambers, wherein it is possible to provide the fuel gas in the high-pressure fuel storage tank from a primary tank, wherein it is possible to withdraw the fuel gas from the primary tank and/or to generate it from a fuel withdrawn from the primary tank along a conversion path, and a gas buffer storage tank connected to the high-pressure fuel storage tank discharges fuel gas from the high-pressure fuel storage tank into the gas buffer storage tank, and the gas buffer storage tank is further connected via a separate fuel gas path to the air intake section of the gas combustion engine.