How far are you getting on a full tank?

How many are going strictly by their gas gauge? If so, they are NOTORIOUSLY inaccurate and will tell you your tank is near empty when, commonly, there's still 4-5 gallons left. Even my low fuel light comes on when mine still has 3-4 gallons left.

Calculate the highway mpg by dividing the miles driven by how many gallons it took to refill it. Then multiply that mpg by 19 to find out the range highway.
Yep, I have 3 to 4 gal left when the light comes on.

At 280 mi, I put in 18 gal or so. In theory, it would go 300. But only if I had a 5 gal can of gas with me.
 
Returning from Western Utah last August, a P2098 (lean) code pops up. Filled up on 85 octane to return home and got 340 miles, no wind, but on fumes by next fill up. Driving a 2005 TJR at 65 mph taching 2500 rpm on old KO 33X10s running 34psi. 141k on odometer. When I first bought it, 250 miles max on a tank (no codes). Engine runs smooth at a steady 210 degrees regardless of terrain or speed. Haven't determined the mileage windfall from the P2098 code and don't want to until emissions time. I'm now getting 15 in town. So much for meeting idiot-light government specifications for our benefit, eh?
 
I never really let mine get lower than 1/4 tank because of where I go in it.

33s right speedo gear 3 inch lift all city little highway driving usually get 17/18mpg
 
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Thats a hell of a drive with three people in an LJ. Did you all still like each other after the trip?
Did it twice. All went pretty well. The backseater was only 5-6. But it's much better with the Superduty pulling a trailer. Fewer stops needed too.
 
I use jerrys method for calculating gas mileage. Miles/gallons filled up.

33s, 3.73s, NV3550, 4.0
Filling up 14-15 gallons at around 180-190 miles. I used to get 15mpg when I bought it, now I get around 12-13 still on the freeway. My P0456 keeps coming on and i already replaced the fuel cap. No visible sign of bad hoses. Thinking maybe its my o2 sensors?
 
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I've been getting 13.5 to 14 MPG with a Golen 4.6L stroker, AX-15, 3" lift on 33x12.5 hybrid tires and 4.10 gears. Driving style is mildly heavy foot and mixture of city and 2 lane county roads. Usually, I fill up when my gauge shows about 1/4 tank and that's after 190 miles or so.
 
True. I was referring to essentially stock tire sizes. With 31s, my Rubi is spinning right at 3K at 75. My YJ is only at 2500 or so with the 5 spd and 3.55s. It will get around 20. Never happening with the Rubi.
 
3" lift and 33" Terra Grappler G2s. Calculated range 266 miles, practical range closer to 210. My wife likes to refill when there's 1/4 tank left. I like texting her pictures of the needle on the E.

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I've been minding my 100 mile average after re-gearing to 4.56 (4.0 4 spd auto and 35's) Fill at 100 miles is about 8.3-8.5 gallons with mixed driving. I know for a fact that I'm getting better freeway in 4.56 gears vs 3.73 i had
 
How many are going strictly by their gas gauge? If so, they are NOTORIOUSLY inaccurate and will tell you your tank is near empty when, commonly, there's still 4-5 gallons left. Even my low fuel light comes on when mine still has 3-4 gallons left.

Calculate the highway mpg by dividing the miles driven by how many gallons it took to refill it. Then multiply that mpg by 19 to find out the range highway.

I use an app called Fuelly to track my mileage. Every fillup I just enter my current odometer reading and the number of gallons when the pump clicks off (as well as the price per gallon and the location). It does all the math for me.

I fill up by the light or the gauge, because I've got anywhere from 40-65 miles left at that point and when fuel stops are 30 miles from one to the next it's easy to overshoot. If I'm on a road trip I won't pass a station without filling up if I'm at or below about 1/3 tank.
 
I use an app called Fuelly to track my mileage. Every fillup I just enter my current odometer reading and the number of gallons when the pump clicks off (as well as the price per gallon and the location). It does all the math for me.

I fill up by the light or the gauge, because I've got anywhere from 40-65 miles left at that point and when fuel stops are 30 miles from one to the next it's easy to overshoot. If I'm on a road trip I won't pass a station without filling up if I'm at or below about 1/3 tank.
I also use Fuelly. I've averaged 11.7 mpg and spent $5,961.71 on fuel.
 
I have had similar experiences to others already noted. Here are my observations in about 4 months with my 2005 LJ Rubi with stock gears and metric 33" tires and a SpeedoHealer to correct distance:

  1. Gas gauge leaves 3-4 gallons at empty
  2. Fuel economy ranges from 13.5 to 14.5 MPG (mostly highway)
  3. Replacing the cold air intake (PO-installed) with a stock intake increased fuel economy by 0.5 to 1.0 MPG
At some point, I plan to carry a 5 gal Jerry can with me and run it to completely empty, just to see how many actual miles I can get on a tank, and how much of the 19 gallons can be used. I'd like to know that because, other than motorcycles, this is the shortest-range vehicle I've ever owned, and it can be tricky making sure I don't run out of fuel in remote areas.
 
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I have had similar experiences to others already noted. Here are my observations in about 4 months with my 2005 LJ Rubi with stock gears and metric 33" tires and a SpeedoHealer to correct distance:

  1. Gas gauge leaves 3-4 gallons at empty
  2. Fuel economy ranges from 13.5 to 14.5 MPG (mostly highway)
  3. Replacing the cold air intake (PO-installed) with a stock intake increased fuel economy by 0.5 to 1.0 MPG
At some point, I plan to carry a 5 gal Jerry can with me and run it to completely empty, just to see how many actual miles I can get on a tank, and how much of the 19 gallons can be used. I'd like to know that because, other than motorcycles, this is the shortest-range vehicle I've ever owned, and it can be tricky making sure I don't run out of fuel in remote areas.
I would never purposely run a vehicle out of fuel, your MPG and tank range can change depending on driving conditions, tire pressure can affect MPG quite a bit as can cold tire travel v hot tire travel
In my opinion reserve should be left as reserve. you have 19 gallons so you can test it every top up as in Jerry B,s method and if you are getting an average of 14 MPG then you already know how far you can get on a full tank 210 miles with 56 in reserve.
 
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In my experience, it’s because it’s a TJ. If there is one thing they all seem to have in common. Regardless of gearing, tire size, curb weight or anything else really they all tend to get similarly terrible gas mileage. 85% of responders to this thread will report slightly over 200 miles to mid 200 mile range per tank. All with varying set ups, yet atrocious TJ mileage. Probably something to do with them being shaped with the aerodynamics of a shoebox…
I have a totally stock 6 speed I have no lift and not even 31,s and I am getting about the same MPG as those with a lift 33,s re gears heavier bumpers and winch, they are a Brick on wheels regardless age or mods
 
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Not necessarily. The best mpg does not always come from the lower of two rpms. After I raised my highway rpms by regearing from 4.88 to 5.38 my highway mpg went up by nearly 3 mpg from sub-12 to 14.6.

Hey Jerry,

This is interesting. Can you say more about when higher RPMs are actually better for your MPG? I'm asking because I've heard it said that the 2.5L isn't actually more efficient than the 4.0, because you have to ride it in higher RPMs in order to keep up with traffic, or when going up hills, etc.
 
I would never purposely run a vehicle out of fuel, your MPG and tank range can change depending on driving conditions, tire pressure can affect MPG quite a bit as can cold tire travel v hot tire travel
In my opinion reserve should be left as reserve. you have 19 gallons so you can test it every top up as in Jerry B,s method and if you are getting an average of 14 MPG then you already know how far you can get on a full tank 210 miles with 56 in reserve.

My average may be 13.4 but from one tank to the next is all over the place. I can tell you that fillup 31 was the result of descending almost a mile in elevation, but the rest don't have a lot of obvious correlations.

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Hey Jerry,

This is interesting. Can you say more about when higher RPMs are actually better for your MPG? I'm asking because I've heard it said that the 2.5L isn't actually more efficient than the 4.0, because you have to ride it in higher RPMs in order to keep up with traffic, or when going up hills, etc.

You're looking for brake specific horsepower, which is a measurement of how much power you get per unit of fuel. It peaks at a certain rpm.

Or in other words, 75% throttle at 2000rpm burns more gas than making the same power as you could with 30% throttle at 3000rpm.
 
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