i got my new pro4x 2011 with 35 miles now has 1k
never got more than 180 miles out of the tank , am averaging
9 mpg max even driving like an old old old lady since got it
dealer said i have to wait untill the break in period which 2k
i don't beleve that will make any diffrence , i got k&n filter in from the second day but all hopes shattared when i still in the 9.3 mpg averrage, whats the problem , what should i check ,
and what to do , or what to ask the dealer to scan for, specialy that am not that experienced with car mechanics, i just love the xterra with all my guts
thanks to every one out there

Not much to go on.

Perhaps the oil for the K&N filter fogged the MAF, and is causing the engine to run rich/less efficiently. This happens all the time.

What tires do you have, and what PSI are you using for them?

Are you in 2wd HIGH?

You don't mention tranny, 6 spd or auto, etc?

Are you using the overdrive lock-out setting?

How many total gallons have you put in the tank since you got it?

Are the diffs getting hot when you drive?

Is there any oil in the coolant/coolant in your oil?

thanks TJ for the repluy
it's 2011 pro4x
5 speed auto tran.
stock tires BFG rugged trail 265 75 16 inflated at 36 psi
i got the car on thanks giving of 2011
so far filling once aweek with very light usage and verrrrrry
light acceleration, ( never exceeds the 2100 rpms) no matter
how many old people screams at me...lol
my deffs temp are normal to the use
always driving in 2wd, never went offroad yet
and no oil colant issues so far ( hope never)
when gas lights comes on i usually fill about 18.358 gallons
in that range and never got more than 179.8 miles out
of that whitch put me at 10mpg at best, dealer says its normal for new car , some x owners on the web said it's ps and it should average good from start , some adviced with resetting ECU
dont know what do u think, am just getting frustrated with me not enjoying driving it and reving as i want , and the wife complain about the gas use, i know it's all been said befor about gas economey, but if i get to that 18, 17, 16, 15,14 or even 13 ill be thrilled so lets cross our fingers and find out whats wrong with it
thanks again man for ur time and pacience for noobs like me

OK, put it into 4wd once in a while to lube that part up (Just don't make sharp turns in 4wd if its not slippery out).

The ECU DOES take time to "learn" how to control that engine, etc.

You may have fouled the MAF when using the K&N too.

Get a can of MAF cleaner (Not brake cleaner, etc...), and clean the MAF (gently), remove the K&N, and put a real filter back in.

I purchased a 2012 4WD 6-speed manual earlier this month (March). I checked the mileage and I'm getting 18+ MPG. You should not use those K&N filters. I have owned three Xterras, beginning with a 2000. I have only ever used genuine Nissan parts. Those K&N filters are impregnated with a substance which can screw up your mass air flow sensor/meter, ruin your oxygen sensors, as well as your three-way catalyst. If you buy a Honda, use Honda parts. If you buy a Nissan, use Nissan parts. You get the idea.

Why the hell is this topic in this section?

There. It's been moved...

Ugh - I hate those things after I took one off my 240sx and found the intake sandblasted.

Stick a regular filter in there and see if it gets better. Then as someone else suggested, clean the MAF as it's probably coated in oil.

Stupid K&N filters... most overhyped piece of crap ever...

I'd vote for the TBS as the most over hyped POC ever actually...but the K&N MAF Fouling /Intake Scouring kit is definitely in the running.