look directly behind the left front bumper(drivers side).I think they put there to protect it while off-roading.
It is located under cab on drivers side on inside of rail.
Fuel pump is located in the Fuel tank. Have to drain the fuel, drop the tank slightly and disconnect thel lines..
275/65/r18t
it is located on the left front of engine in front of motor mount regradless of what any book may tell you
The filter is located on the cross member in front of the gas tank. Remove the shield at the front area and it is mounted to the shield. 10 minute job.
Check the fuel lines on the drivers side right beneath the door.
I have a 99 with a 2.7 and mine is located under the intake manifold on the left side of the motor mounted to the engine block. It can be seen through the driver's side wheel well. I have a 2001 Tacoma Double Cab 4x4, and he fuel filter is located under the chassis on the driver's side about under the driver. You can crawl under it and see it.
If your 03 is the same as my 04, then the fuel filter is located at the right rear under the vehicle. Be careful when removing it, as the bracket that holds it in place can become fragile over time (corrosion, etc.).
It does not have a cabin filter.
A 2005 Dodge Neon does not have a cabin filter.
http://wiki.answers.com/Q/2006_nissan_frontier_4x4_crew_cab_cabin_filter location
4x4 / regular cab / short wheelbase - 24.5 gallons 4x2 / regular cab and all Super Cab / short wheelbase - 25.0 gallons