The effects of hydrogen and carbon monoxide addition on premixed methane/air flame dynamics in a heated narrow channel are numerically investigated using a time accurate, compressible flow solver along with the DRM-19 reaction mechanism. By adding a small amount of either H-2 or CO, flame instabilities present for the pure CH4/air combustion in the form of flame-extinction and re-ignition could be effectively suppressed. This suppression can be attributed to a few important elementary reactions, that play a dominant role in contributing to the heat release rate, getting enhanced with H2 or CO addition. This leads to a higher flame propagation speed and a shorter flame-extinction period, and eventually leads to flame stabilisation after a few cycles of spatial oscillations. (C) 2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.