runs rough on 1991 Saab 900

when i start the car it acts cold,if i reset the check engine light it runs worse i have changed the fuel filter,o2 sensor and cleaned the map sensor the plugs are good,not sure i think its vacuum or sensor problem,it seems to want to die after you put in gear and has no power could it be the catalytic converter?thanks

Asked by for the 1991 Saab 900
I'd say, look for an intake air leak.
I suppose it could be the catalytic converter, it could be getting plugged up. If so, you could possibly be able to tell by putting your hand up to the exhaust outlet pipe and feel a steady flow instead of pulsing exhaust gasses.