Originally Posted by Burnman
Last time I checked, Carbon Monoxide was not a fuel. Cats are not oxidizing NOX. Nor was my car designed to run rich at normal driving conditions. If they need more heat in the catalyst, they would actually run leaner to elevate EGTs. If all they did was burn there would be no need for the expensive precious metals, and they wouldn't be catalyzing anything. Unburnt fuel is primarily dealt with by the EGR system.
EGT alone are not enough to sustain the reaction. Ask any good Subaru tuner- when you are in closed loop cycle the air to fuel ratio constantly fluctuates in order to keep the catalytic converter operating. Go out and log your car, you will see it.