Lots, that is the problem. Stumbling, stalling, and smoke often indicate a waaay over rich condition. Code 34 is the Mass Airflow Sensor ona "C" engine (black square thingie with three screws on side of throttle body.
Since MAF is a major contributer to the mixture setting, that would be a good place to start. When you pull it out there are two coils of wire visible. The MAF is very expensive and the coils are delicate.
Personally I'd use a scan tool to take a snapshot when the problem occurs but first you might just R&R the MAF connector a few times, it might just be a bad connection.