Q: How to service fuel injectors and Fuel Rail on Nissan Maxima?A: To service fuel injectors on 1995 and later models, you can access the front bank without removing the upper intake manifold, but the rear bank requires its removal. Individual fuel injectors can be serviced without detaching the fuel rail. Start by relieving fuel pressure and disconnecting the battery's negative cable. Remove the air intake plenum and disconnect the fuel injector electrical connectors. For 2003 and earlier models, remove the injector cap screws and cap, then pull the injector(s) from the fuel rail cup. For 2004 and later models, remove the clip and injector from the fuel rail. Inspect and replace worn injector O-rings, lubricating new ones with oil. If removing the fuel rail assembly, disconnect the fuel lines and remove the retaining bolts. Inspect and replace worn fuel rail insulators, lubricating them before reinstallation.