We recommend replacing all injector O-rings even when only one injector O-ring or seal is leaking. On most fuel rails, you have to remove the entire assembly anyway, so replace all of the O-rings/seals to avoid having to remove the fuel rail later. First, relieve the fuel pressure. Then, disconnect the cable from the negative battery terminal. Remove the engine cover, if equipped, and the air intake duct. On V6 models, remove the upper intake manifold. Disconnect the electrical connectors from the fuel injectors, unbolt the harness and set the injector harness aside. Remove the fuel rail mounting bolts, the fuel rail and the fuel injectors as a single assembly. Remove the fuel injectors from the fuel rail. If you intend to re-use the same injectors, replace the grommets and O-rings. Installation is the reverse of removal. Be sure to use new injector O-rings and tighten the fuel rail mounting bolts to the torque.