# 10mpg highway wtf?



## lilredtruck (Nov 16, 2008)

just drove 12hrs to visit a friend in aheville n.c. i ususally get 14mpg in the city so i figured the mileage should go up on the highway. NOPE i seemed to go through a tank pretty quick i was like wtf? so reset the tripometer and calculated after next fill up. i got 10mpg. im like how can it go down running on the highway? truck has new plugs wires cap rotor. new alignment which fixed the wondering steering wheel and no coast on a slight incline after a complete stop. just got 4 new tires. i did change wheels im running 245/75/16"s which measure to a 30 1/2 clutch is strong but im thinking the wheels may have changed the gear ratio a bit cause 5th gear is so gutless on the highway i had to drive the whole trip in 4th which made going up and down the hills in ky and nc a lot better. any suggestions would be helpful maybe i can a change of some sort before i head back to indiana on monday.


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## dvdswanson (Nov 6, 2005)

what yr and eng.? 2wd or 4wd? when was the last time you changed the fuel filter?


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## pedxing (Jan 2, 2008)

Any recent brake work when you put the new wheels on? Any burning smells after you stop? Any resistance at all?


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## Peterdaniel (May 24, 2005)

This is an easy one

Your tires are way to big.

Assuming a standard size tire of 235/75/15 Your new tire as listed above being a 245/75/16 would increase your diameter from 28.9 inches to 30.5 and DECREASE your rev's ( of the tire iteself) per mile from 698 to 662 hence turning your odometer slower.

Now assuming your truck is a 4 cylinder, you are asking ALOT for that motor to overcome.

Being a Nissan truck means its heavy, being a 4x4 is even worse. And if you are an extra cab.. get my meaning? Plus you have poor aerodynamics naturally and then you are pushing it through the wind at highway speeds and up hills in 4th gear.

So your mileage will suffer anyways but putting the larger tires on not only gives the truck even MORE inertia to overcome but doesn't give you an accurate reading in the first place.


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## lilredtruck (Nov 16, 2008)

ahhh now i see said the blind man to his dog. thanks for the input guys. no brake resistance it rolls freely when i push it. i was going to put the original wheels back on before i left but wasnt able to due the really cold weather we got. oh yeah fuel filter was done with tune-up


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## 68Datsun510 (Jan 19, 2009)

ANd how fast exactly do you like to drive??? ANything over 65 will kill your mileage in anything not shaped like a honda civic! lol

Look at it this way, I squeezed 31 mpg out of a Datsun 510 with a Z22E, 720 truck 5 speed, and 3.7 subaru LSD rear end, a 510 is horrifically unaerodynamic. I did it because I drove 55 mph following trucks in the slow lane, 310 miles on 10 gallons of fuel.

Drive the same in your truck (on the longer trips obviously) , and get reasonably sized tires and youll be fine.


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## the red mule (Feb 7, 2009)

hey lil red this here is the red mule lol,i live in indiana also but im working in iowa right now but i hav a 92 with a 4 popper,4x, 5 speed and ive been driving about one hundred miles one way on a little less than half tank it takes about 5 gallons to refuel and im running 31x10.5 r15 mudders


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## lilredtruck (Nov 16, 2008)

thanks for the input guys unfortunately i still have to drive back to indiana but after that if i take any more really long road trips i will put the oe tires and wheels back on before hand. i was going to do that but i procrastinated and now i'm paying for it. lesson learned.


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## Nissanman7166 (Feb 12, 2009)

the red mule said:


> hey lil red this here is the red mule lol,i live in indiana also but im working in iowa right now but i hav a 92 with a 4 popper,4x, 5 speed and ive been driving about one hundred miles one way on a little less than half tank it takes about 5 gallons to refuel and im running 31x10.5 r15 mudders


lol, mines about the same as yours but a year newer and an Xcab. I've got the same size tires......really not the greatest gas mileage is it??? But love the truck to death regardless.


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## mknight759 (Dec 24, 2008)

i have 31's on a 95 4wd 4cyl 5sp i get 18-20 mpg i though that was not to bad seems to be a good little engine


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## lilredtruck (Nov 16, 2008)

yeah things are off a bit with the bigger tires. i reset the tripometer when i left my friends house in NC, according to mapquest it is a 620 mile trip when i got home the tripometer read 543 miles so things are definatley moving slowly.


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## the red mule (Feb 7, 2009)

:fluffy:like i said earlier that im still getting about 19 in my truck. i think im going to see if i can find a bit lower gear set for it and install them to corect my underpowerdedness while on the highway.lol


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