Without knowing the details of when and under what conditions the motor quits, or which of the three available engine sizes your car has; it is hard to pinpoint a likely cause. In general, I would suggest replacing the fuel filter, air filter, plug wires, and spark plugs; and cleaning the mass airflow sensor, fuel injection throttle body, and idle air control valve. Please be aware that specialized cleaning products and techniques are required for the mass airflow sensor; in order to avoid damaging it. It can only be cleaned with airflow sensor spray (most commonly made by CRC). Do not touch the sensor element or scrape it with any object. Just spray the sensor element until it is shiny clean.
Another thing that would make the motor quit is a defective crankshaft position sensor.