where is the fuel filter on my montero xls?

What size engine do you have?

3.5L 4wd its not the sport.

I have the check engine light on, when I put it on my scanner
it was pinpointing lean sytem
the egr valve is working, Ive cleaned the carbon out, the sensor was changed and now I was looking to replace the fuel filter, to see if it corrects the problem.
the codes im getting
p0174 p0171 p0401

What sensor did you change?Also have you checked for vacuum leaks or the actual fuel pressure?

the DPFE sensor, ive replaced all the Vaccum lines
I have no way of checking the pressure.

These are lean codes, so we need to find out what we have more air or less fuel.

Let's start with checking the fuel pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If the pressure is correct, then we need to move onto checking for a vacuum leak.

Even though you replaced the lines you can still have an intake leak so let's run through this guide:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Lastly here is a guide that talks about this issue and will get us further down the line if these two things check out:

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

Please run through this info and let us know what you find.

Thanks