One embodiment is a system comprising an internal combustion engine having one or more non-dedicated cylinders and one or more dedicated EGR cylinders configured to provide EGR to the engine via an EGR loop, a first spark plug coupled to each of the one or more non-dedicated cylinders, and a second spark plug coupled to each of the one or more dedicated EGR cylinders, wherein the second spark plug has a physical or dimensional characteristic that is different from the first spark plug. In certain forms each of the non-dedicated cylinders has only one of a first type of spark plug and each of the dedicated EGR cylinders has only one of a second type of spark plug. One or more of the characteristics that may vary between the first and second types of spark plugs include spark gap, electrode diameter, heat range, and ion sensing capability.