2004 Volkswagen Jetta my car shuts of randomly

Check for vacuum leaks and the idle air control valve.

Check for stored fault codes and check your fuel trim values with a capable scan tool (this will tell you if you have a vacuum leak or not).

Clean the throttle body and perform a "Throttle Adaptation" (capable scan tool required) if no faults are found with the above.

If no scan tool is present, clean throttle body and see if the idle is now "higher". This will confirm that the "learned throttle position" was at
its end and air flow has been restored with the cleaning.

Thomas