Car runs rough then rides normally after I drive for a while.

When I first start my car in the morning, I have a rough idle and a rough ride for a while and then the car lugs for a minute and then drives normal. There seems to be a rattling sound coming from near the Catalytic Converter or the exhaust tip. There is no funky sounds coming from the engine. I know that cleaning the Mass Airflow Sensor, replacing the air filter, checking the fuel pump and checking the catalytic converter are some options but doing all of them takes some time. Is there an easy diagnosis for this problem?