A method for reducing the amount of carbon monoxide and oxygen emissions in an oxyfuel hydrocarbon combustion system, comprising the steps of feeding defined amounts of hydrocarbon fuel and an oxidizer (e.g., air) to one or more combustors in the engine and igniting the mixture to form a first combustor exhaust stream; determining the amount of carbon monoxide present at the head end of a combustor in the initial combustor exhaust stream; identifying one or more target locations within the combustor at a point downstream from the first exhaust stream for injecting free hydrogen and a supplemental oxidizer; injecting hydrogen and the supplemental oxidizer into the combustor at specified downstream locations based on the amount of detected carbon monoxide; and injecting a diluent (e.g., CO2) into the combustor at a point further downstream in the combustor exhaust to control the exhaust temperature.