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I have a 2017 JKUR, 6 speed, stock, my widow sticker say I should get between 16 city to 21 highway, averaging 18. Here is a look at real world numbers, I would say that about 70% of these miles are highway all Florida flat land . I know it a jeep and the gas mileage is garbage. My question is why is my onboard computer saying that I am averaging 18.7 mpg when that is not the case? Is my computer bad or is the software wrote to fool the customer.

mileage gallons price miles driven mpg
300 19.356 45.47
577 18.641 42.11 277 14.85971783
820 16.864 37.76 243 14.40939279
1105 18.906 41.57 285 15.0745795
1417 18.676 38.83 312 16.70593275
1686 18.295 38.04 269 14.70347089
1895 14.356 29.85 209 14.55837281
2193 17.977 37.37 298 16.57673694
2480 18.035 38.37 287 15.91350152
2687 12.898 39.37 207 16.04899984
 

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The computer is estimating your miles per gallon. It does not actually measure how much fuel is being used, it is estimating it. It is not at all odd to me that its estimation is off by a couple miles per gallon.
 

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Trip computers are always off, for every manufacturer.... but I have never seen them off by THAT far !!

My Toyota Highlander's hand calculated mpg has been *almost* dead on to the trip computer mpg....within about .5 mpg typically.
 

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Just thought I'd pop in and say "It's a Wrangler, why do you care about MPG?".

Looks like you're averaging 15.42786 mpg , about 35% more than my average. A couple factors that may explain some of the discrepancy:
1) EVIC doesn't actually measure the fuel consumption rate, only estimates.
2) The estimates are based on the fuel level sender reading, which as we all know spends a LONG time above 1/2 and drains quickly under 1/2.
3) The amount of fuel "used" between fill-up and when the fuel level sensor starts reporting less than 100% full is Zero. Say you have a 20-gal capacity tank, the sensor reports 100% until you're under 19 gallons. That 5% of the tank is ignored, and unreported as consumption in the equation.

Finally, why does it matter? Have fun in your vehicle!
 

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When Jeep puts the mileage on the sticker, it's for the best case scenario. Probably a stripped Wrangler with whatever transmission, 3.21s, and the little tiny street tires on the Sport models. They get that one EPA certified.

Are you going to get that with a stock Rubicon? Probably not. Between the gearing, MTs, raised a little, all chipping away at that.

Just wait till you lift it and put bigger tires on there. I figure another couple hundred pounds added for various things. I average a hair over 15 mpg now.
 

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My commute is ~~50/50 highway and back-roads. I get 18mpg +- a couple of tenths, every tankful. Typically hovering right around 70 on the highway. 33" tires are the only driveline change I've made to my '15 JK WW. Std 3.73 gearing.
 

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lol I think the default average computer reading always ends up being 18.7. Road trip this weekend booked a 20.7 at the pump with some stop and go traffic on the freeway, but the computer read 18.7. Stock rubi, 4.10 gears, pretty sure I had a tailwind though ;)
 

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My computer's avg mpg calculation over the lifetime of the vehicle was only off by around .2-.5% compared to my calculations at the pump.
 

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Yea, the MPG display accuracy on the JK is horrible. I rarely look at it anymore.

The EVIC reading on my '16 JK was actually worse than my last hand calculated mileage at the pump.

The display showed 14.6 MPG but dividing the miles I went by the gallons I took gave me 17.2 real MPG .
 

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I don't look at the MPG display anymore, either. It is always high by a substantial amount. I measure my MPG using a great little app: RoadTrip. Here are the last 10 actual MPG readings for my stock '17 JRURHR:

16.27 (9237 miles on odometer)
14.53
16.31
14.69
15.62
14.85
14.82
15.45
14.61
14.17 (7494 miles on odometer)
 

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The computer seems to average your current mpg for example if you are cruising along on the highway it will go up, if you are stuck in a traffic jam it goes down. It shows you an estimate of where you are currently at. I always hand calculate. The computer is usually .5-2 mpg higher.
 

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Remember that the EVIC calculation is a point estimate, as others have mentioned. Your at-the-pump calculation is over the whole trip. As an example, I topped out at 18.8 mpg this tank, (and I don't think I'm halfway through it yet.) but I'm down to about 16.0 now due to stop and go, and waiting in line at the drive-through. For the most part I'm on surface streets with ~1mi between lights, speed limit 50mph.
 

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2015 JKU Sport with automatic. I got 16.5 when I first got it, but once I learned how to drive it I get 18+. I got 18.3 on the last fillip and 18.9 on the one before. Like all vehicles, Sudden starts (and stops) and accelerating to 70mph halfway down the on-ramp takes it's toll on milage.
 

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Oh,Boy, come up to the Northeastern states this winter when you hit the snow season, and see how much you get with 4 WD... Then it really drops. I usually lose 2- 5 mpg....Slow speed and 4 wheel drive sucks it up!
 

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Part of the question needs to be how accurate or consistent are gas pumps in their automatic shut-off thresholds? I've never been sure. Maybe one station's or pump's full level is significantly lower than another's. This would give a falsely higher mpg rating by manual calculation, right?
 

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2017 JKUR with the 5 spd auto here and on the way home from the dealership in Idaho driving through central Oregon my info display was showing 22 mpg at one point. Just before the fill up in Prineville, Oregon it was reading 20.4 or close to that. When I filled up and did the calculations they came out to 20.2 mpg.

All stock and I drove it at the speed limit, no more, sometimes a little less through the twisties. 80 mph in Idaho, 65 mph on the eastern side of Oregon and 60 mph on the west side. ALways takiong my time to accelerate up to speed.

My daily commute is seeing numbers closer to 15 mpg. Again, I am light on the throttle 90% of the time.
 

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Been averaging 32k miles/year on my JKUs. I take a lot of vacations.

I always look at miles driven and gallons used. Just did 3456 miles on interstate 70 (Ohio > Colorado > back). Took a 2013 unlimited sport with 3.21s and factory Rubicon (BFG) tires. Got around 340 miles per tank just into the fuel warning light - close to 19mpg. Usually get around 275-285 on same tank with '14 JKUR 3.73 with factory tires. Keep it around 75, much higher and MPG tanks (which isn't about money, it's more frequent stops). Lighter SRA's and sticking around 70 will yield higher numbers. Heavy 285 KM2's and 4.10s get me around 14mpg.
 

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The only way to know for sure is to top it off, and I do mean top it off until it wont take any more gas, drive it till its down below 1/2 tank, and then fill it back up to the same point. Do this a minimum of three times and then take the average. It wont tell you specifics for highway or city, but it will give you a very accurate all around.
 

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The sticker for MPG was for a Wrangler Unlimited Sport with base tires and a 3.21 gear ratio... Not for the JKUR. The EPA estimate is based on a manufacturer's model, engine and transmission. They will submit the most fuel efficient model in the line up for testing which will be a 3.21 sport with as little features as possible to save weight. Then that sticker will go on every vehicle with that model/engine/transmission option. If the EPA tested you JKUR it would be more like 13-19 MPG.
 

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Unless they indicate direction of travel and direction and windspeed they are all lying.... On highways can get around 15 mpg with the wind at my back. Can lose 1-2 mpg going straight into the wind. Normally i get around 13-15 mpg when i figure it out manually , mix of in town and highway. Anyone who buys a jk thinking they are gonna load it up with parts and be around 20 mpg is seriously lying to themselves.
 
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