Why Does My Gas Mileage Suck?

[Gfcronus]

I’ve had my 2025 JLU Willy’s for about three months and I am averaging 16.8 mpg. My 2021 JLU Rubicon was getting 19.8 mpg. Same mix of highway and city, same engine (V6), same transmission (manual), same driver (me). What gives?

Sponsored

 

[mrtm1970]

Different Axle gearing? Different tire size?

 

[mysto]

My 2020 was getting 15 the first few months, then it slowly increased to 20-ish.

One possibility is to give it some time. Nothing wrong with asking the shop to take a look.

 

[GabeBoyTheGreat]

I’ve had my 2025 JLU Willy’s for about three months and I am averaging 16.8 mpg. My 2021 JLU Rubicon was getting 19.8 mpg. Same mix of highway and city, same engine (V6), same transmission (manual), same driver (me). What gives?

I have the same issue. 2025 Willys JLU V6 manual. It gets a whopping 1 MPG better than my 2018 Sport JL V6 manual with 3.5" lift and 35s; it seems like it should do better.

My best guess is the tires. The Willys comes with M/T tires as opposed to the Rubicon with A/T tires. Additionally, the specific tires on the Willys are about 10 lbs heavier each compared to the Rubicon tires (61 vs 51 lbs). The 33s on the Willys weigh almost as much as my 35 Duratracs (68 lbs) on my Sport

So my theory is a combination of tire weight and tread pattern. Since your Rubicon gets better MPG, this further supports my theory.

 

[Omen]

37 psi in 285/70-17 I get 21.5 mpg. 28 psi in same tires and everything else as equal as possible, 19 mpg.

Maybe there is an answer in that?

 

[Operative73]

2020 2 door. 32" w 3.5" lift, steel bumpers, winch, 3.6L/8auto pushing 3.45 gears . I get about 14 and a half to 15 miles per gallon City.(southwest PA, you either going uphill or downhill)

 

[Twisted10]

laffs in 392 on 38's

 

[WannFly]

you guys track gas mileage? man there are some brave souls here.

whats next? upgrade cost tracking?

 

[Operative73]

you guys track gas mileage? man there are some brave souls here.

whats next? upgrade cost tracking?

I don't really actively track it it just shows up on my dash in the corner. even though I hate the phrase, "it is what it is". I need gas when I need gas, and I didn't buy a Wrangler for mileage.

 

[TheRaven]

...the specific tires on the Willys are about 10 lbs heavier each compared to the Rubicon tires (61 vs 51 lbs). The 33s on the Willys weigh almost as much as my 35 Duratracs (68 lbs) on my Sport.

Very likely the culprit. I have pretty much the exact same JLU but on 35" Territory MTs (not a true M/T) that weigh 50lbs each and my daily driving fuel mileage sits around 19 consistently.

Tire weight kills fuel mileage big time.

 

[azjl#3]

How many miles since new?

I have tended to find, the drivetrain, axles and such, do not break in until 6,000 miles or so on the clock, all have had MPG improvements of about 1-2mpg after 6,000 miles. My 24 just started getting 18.5 after doing 16 plus until I hit 6,000 miles.

 

[c20040215]

you guys track gas mileage? man there are some brave souls here.

whats next? upgrade cost tracking?

You should but not necessary for cost.
I track it (or pay some attention to it) for consistency sake. Whenever you see big fluctuations, that is a good indication of something is not right. Like you want to take a glance at your dump before flushing. Making sure there isnt weird color or something.

 

[JPAloha]

you guys track gas mileage? man there are some brave souls here.

whats next? upgrade cost tracking?

I look at my MPG figure as a fun challenge (roads here are pretty boring) and a way to compare our three JL’s. Far from my first Jeeps so not expecting stellar results.

Recently, I did have to add up the cost of mods on my 2019 for an appraisal (just in case there needs to be a conversation with the insurance company). I’m glad there’s no labour on that number as it was scary enough as is .

 

[RatZero]

I wouldn't really judge gas mileage until you've put at least 10k km/7k miles on the engine. That said, turn on the gear indicator and force an upshift when appropriate when driving. The transmission tends not to upshift when it should between 6 and 8th gear and that adds about 15% to fuel usage.

 

[JT23JL]

Also,, your 2021 model probably had a Front Axle Disconnect. Your 2025 model probably does not have the Front Axle Disconnect. The Front Axle Disconnect provides slightly improve gas mileage.

Sponsored