On this parts fiche the Spring, Throttle 2 is the most specified component.
A sample from the products for the Injection Pump include: O-ring, Pilot Screw, Screw, Throttle, Sensor, Pressure, Screw, Pan Head(6e7).
The most reasonably priced component used on the Fx1000-b/c-b 2003 Usa Injection Pump is the Screw, Pan Head(6e7).