I was wondering about a stopped up catalytic converter?

its your timing, go to a shop and get them to change your timing belt. It is not your fuel pump nor is it your catalytic converters..... when your timing is off it causes the stroke of the piston to not be in tune with the valves opening and closing. for example on the compresion stroke the exhaust valve might open a little causing loss off compresion (power) and pushing unburnt fuel into the exhaust