You need to disconnect the negative battery cable, relieve the fuel system pressure, remove the upper intake manifold, the fuel pipe retainer clip bolt, the engine fuel feed pipe from the fuel rail, the engine fuel return pipe from the
Fuel Pressure Regulator, and the fuel feed and the fuel return pipe O-rings, discard the O-rings, disconnect the main fuel injector wiring harness connector, pull up the lock release on the fuel injector electrical connectors, depress the lock tabs and disconnect the fuel injector electrical connectors, remove the fuel injector wiring harness from the fuel rail, disconnect the engine coolant temperature (ECT) sensor electrical connector and remove the fuel rail bolts, the fuel rail assembly and the fuel injector O-ring seal from the spray tip end of each injector, and then discard the O-ring seals if damaged.