In this work, we have investigated the opportunity to use fully and partially coated monoliths as catalytic combustors for syngas/methane mixtures in the presence of significant carbon dioxide (CO2) partial pressure. In particular, the effects of the syngas-to-methane (CH4) ratio and CO2 content on perovskite-based monoliths were studied to verify the ability of carbon monoxide to sustain CH4 combustion also in the presence of CO2. Results have shown that syngas substitution to CH4 is effective in improving the resistance to the inhibiting effect of CO2. A novel light-off strategy has been proposed: regardless of the partial pressure of CO2 the catalytic combustor is first ignited with a syngas-rich fuel and, after ignition, syngas is partially replaced by CH4. It has been found that the operative window of the reactor is dependent on the coating degree, the fuel composition, and the partial pressure of CO2.