Execution order
1. Reduce the pressure in the fuel system (see p. 3 of subsection 6.2.2).
2. Remove the injector holder.
3. Pull the injector upwards with the sealing ring by the nut that secures the fuel line to it.
4. Loosen the fuel line fastening nut, holding the injector with a hex key, and disconnect the fuel line from the injector.
5. Remove the remaining injectors in the same manner.
6. Install the fuel injectors in reverse order, replacing the injector seals.