Alright, I know that the service manual calls for changing the plugs at 100k. I have already changed my cap and rotor at approx 35k. My X has approx 78k on her right now. My gas mileaga is somewhere between 9-11mpg.

I was wondering if I changed the plugs, cap, and rotor if the mileage would improve? I really don't expect this to turn into another gas mileage thread, but ways of improving it with high mileage trucks.

Do y'all with this many miles or more find yourselves getting worse and worse mileage?

That's some pretty poor gas mileage. I can manage 9 mpg pulling a 4000 lb. trailer.

Um, no.

78,000 isn't high mileage. At 55,000, I get consistently the same mileage no matter what (seasonally adjusted, of course). My 4 cylinder Trooper got consistent mileage at 164,000 too.

If I were you, I would dump in a can of BG44K, check tire pressure and try changing all filters and plugs and see what happens.

Gap the plugs then check the timing.

Goto the bottom of this page .

I got close mileage and my average travel mpg is like 20+, with 31" tires , ConFerr rack + couple of KCLites sticking out..

That is unless i am filling at Phillips66 , then its like 14.. In city its about 14+/ 12+ with Phillips

Ways to improve - better oils (i am sticking with Royal Purple lately, it seems to outdo other stuff i tried so far), better petrol (i.e one without water ) , tire pressure (mines are between 31 and 35, depending on season), alignment/balance checks (duh), driving habbits (har har har).

Well I am driving with 32" MT's, a rack and lights as well. I have always used Mobil Synthetic and get the truck balanced and aligned monthly. I will try a different gas, but usually always go to Citgo or BP because they are American owned.

I'm not sure I'd consider British Petroleum to be American owned (though they do own Standard Oil and Amoco). My understanding is that's it's a multinational--execs are both British and American, with corporate HQ in London.

You gert your X aligned every month??? Did you win the lottery or something?

The 32 in. MT's are killing you. With my pathlooser, going to MT's, stock 31 in., would cut one mpg off the economy. Switch back to an AT tread, mpg went back up. The extra wind resistance from racks and lights won't help either.

dave and xtoy - but if you wanna look , pay the price

Spent $130 at Merchant's Tire Center and received a three year get aligned any time you want service plan. Sounded like a good idea, so I take full advantage of it.

Yeah, OK, but it seems not everyone with the MTs and racks are getting as poor as mileage as I am.

Could it be that my MAP sensor needs cleaning? Would running the truck on Advanced Auto's diagnostic machine yield any results?

Uzbad ,you said in your post,that your running 30-35 psi in your tires.I just replaced my tires about two weeks ago [went with bfg long trails,31 10.5x15.man what a change for the better!]would you reconmend this instead of the 26psi in the book?

My city only driving gets me about the same mpg. Highway/freeway only driving gets me about 14 mpg.

I have...winch, Calmini winch bumper & front skid, 3" susp. lift, & 32" Geolander AT. No roof basket.

I'd agree with DaveDatsun...I also think that I get what I get from running 32" tires. :rolleyes:

Could it be that with 32's you aren't able to calculate mileage correctly? What I mean is...your odometer reading is gonna be a little off (low) with that size tire. Plus, the weight of the 32's don't help much either. Try driving around 100 miles and then converting it using XOC's calculator thingy. 100 miles an your odometer might be like 125 miles in actuality if you compensate for the tire size.

I have 31s and after 3 years my odometer reads something like 22K miles. In actuality it should be around 27K.

Just a thought. But man, 9 mpg is really crappy... something has be off (besides the Xterra's overall crappy mileage to begin with).

I get 14 - 17 MPG all the time (city or highway) on 32" Dueler M'T's at 32 p.s.i, and my truck weighs 4,750 lbs without me or gear in it. If you're really only getting 9 MPG you should be looking elsewhere for the problem. Only time I got 9 MPG was when i was in 4L and playing in the sand dunes. On my 31" A/T's I get 15 - 19 MPG.

The mileage thing is easy to figure. It's based on the diameter of your wheels. If you divide the diameter of your larger tires by the diameter of your stock tires (the ones the X was 'calibrated' with), you will get the ratio of miles actually traveled vs odometer miles.

For Example, if you changed from 28" tires to 31" tires, the ratio 31/28 = 1.11, so for every mile your odometer traveled, you actually traveled 1.11 miles.

Of course, all this assumes that a) your odometer is properly calibrated and b) that your tires are perfect circles. Still, it may help you feel better about driving a brick on wheels with added air dams and tires so fat they add resistance like dragging a cow.

My mileage sucks, too. My solution is to drive someone elses car most of the time, and use their gas.

What bad mileage?!? I got 300 miles out of almost a tank and a half!! Granted I was doing 80 the whole way :p

That's nothing to brag about. You should be getting more like 300 miles out of one tank.....not a tank and a half.

FYI

My X is still stock & I get 14-17 city & 19-24 on the highway. I consider this to be great for a brick on wheels. All I've done is oil changes & tire pressure.