2001 Mitsubishi Galant Stalling while stopped

If the Catalytic converter was clogged the engine would have problems at higher RPMs and under a load. If the catalytic converter element was ineffective you would have O2 sensor codes and a check engine light. This would effect how the engine ran, and could cause simular problems. The problem is the air fuel ratio at idle is off. This can be caused by a sensor reading like the O2 sensors being off or an actuator like IAC being off. Other sensors to check are MAP/MAF sensor

There is no electrical connector to control the Catalytic converter. The Catalytic converter is just a honey comb element inside a tube that causes the exhaust gases to convert into safe elements. This is automatic. You can unplug the O2 sensors and put the engine into limp in mode which will burn rich and eat gas rather thatn stall. A Torque Converter is in the transmission. This may have a controller you can unplug to get desired operation, but I doubt you want to do that. A torque converter that is dragging on the engine at all times could cause your problem, but this is expensive and rare. This would cause the car to be harder to keep stopped and roll faster than normal at idle.