How many catalytic converters does the 2007 Ford Expedition have?

The 2007 Ford Expedition system has two catalytic converters. One at the front end and one at the back end of the vehicle. A catalytic converter is an exhaust emission control device that reduces toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction (an oxidation and a reduction reaction). Driving with a bad catalytic converter is not too dangerous. If some small parts of Your catalytic converter are plugged, You can still drive Your car as usual. In the case that the catalytic converter is plugged, it will prevent You from running Your vehicle.