The Infiniti QX4 uses an in-line fuel filter, which is usually located on the passenger side frame rail near the back wheel. The fuel filter keeps debris and moisture that might accumulate in the fuel tank from getting into the fuel system. The fuel injectors spray tiny droplets of fuel into the intake manifold, and the smallest piece of dirt could clog the injector, disturbing the air/fuel mixture. Once the mixture is disturbed, one or more sensors will sense this and turn the check engine light on.
Tools Used: Tools, Rag, Set of wrenches, Fuel filter removal tool, Engine oil
Replace the Fuel Filter
Open the hood and find the relay box. It is located near the driver’s side fender well. Lift the cover off. Using the diagram on the inside of the cover, locate the fuel pump relay. Pull the relay out of the box. Crank the engine over three or four times to relieve the fuel pressure in the fuel system. The QX4 will not start.