Cabin air filters not common till after the 2007 model year and beyond. Your 03 Nissan altima will not have one.
Its located on the top firewall on the driverside.
The 1999 Nissan Ultima fuel filter is located in the fuel tank. The fuel filter is not visible and is very costly to replace.
A 2006 Nissan Altima has a fuel filter located along the vehicle's frame. It is positioned just past the fuel tank for maximum efficiency.
behind the glove box
On the website www.nissanclub.com they have an excellent FAQ section for 2007+ generation Altima's. In it you will find a how-to with pictures on how to change your cabin filter.
The oil filter is located right above the steering rack on the passenger side.
Most are located behind the glovebox. Look in your owners manual, they usually show you how to acess and change.
You need to change the filter with every oil change. Nissan recommends every 3750 miles.
Its located in the fuel tank. It is not a serviceable part
It is located on the inside of the fuel tank, and will never need servicing!
On the firewall on the driver side under the hood.
== Answer The PCV valve on a 1993 Nissan Altima is located under the intake manifold just above the oil filter. You have easier access if the oil filter is removed. Not so easy...