Relieve the fuel system pressure, then disconnect the cable from the negative terminal of the battery. Raise the vehicle and support it securely on jackstands. If you're working on a Frontier or Xterra, raise the front of the vehicle. If you're working on a Pathfinder, raise the rear of the vehicle and be sure to block the front wheel to prevent the vehicle from rolling off the stands. On Frontier models, the fuel filter is mounted to the right frame rail, near the fuel tank. On Xterra models, it's located on the crossmember just in front of the fuel tank. On Pathfinders, it's under the vehicle, near the rear differential. Clean off any dirt surrounding the fuel inlet and outlet lines. Loosen the clamps on the inlet and outlet hoses, then detach the hoses from the filter. Have spare rags or a small container to catch or wipe up the gasoline that will spill from the filter. Unscrew the fuel filter mounting bracket bolt and remove the fuel filter from the bracket. Installation is the reverse of removal. Be sure the filter is installed facing the proper direction. If spring-type clamps are used, it's a good idea to replace them with screw-type clamps.