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Milage not what I expected

Nwjeepguy

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I recently traded a 22 grand Cherokee overland with a v6 penstar engine and replaced it with a 24 gladiator with the same motor. My question is this I was consistently getting between 18 and 20 mpg in the Cherokee but the new jeep seems to be much lower, 14 to 16. The rug has 10,000 on it now.should I be getting better mpg then that? For clarification it's a Rubicon on 33's with 4:10s and automatic

Jeep Gladiator Milage not what I expected 20251118_080047
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Bandit’s Lair

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I’d think it would be slightly better than that but terrain and winter weather/wind may be having an effect. I’m hitting 15-16 on 37” with 4.88. Do keep in mind it won’t be Cherokee numbers though. You now drive a cinder block when it comes to aerodynamics. As long as it’s consistent over a long period of time I wouldn’t worry too much about something being wrong. If it drops 25-30% in a short time with no changes made then I’d start searching for issues.
 
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Nwjeepguy

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I’d think it would be slightly better than that but terrain and winter weather/wind may be having an effect. I’m hitting 15-16 on 37” with 4.88. Do keep in mind it won’t be Cherokee numbers though. You now drive a cinder block when it comes to aerodynamics. As long as it’s consistent over a long period of time I wouldn’t worry too much about something being wrong. If it drops 25-30% in a short time with no changes made then I’d start searching for issues.
While I totally agree with the block analysis and understand about the areo dynamic factor , I see a lot of posts with people stating much better mpg numbers and that's my reasoning for asking.
Thanks for your input
 

UTRocky

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What kind of TIRES ya got? Road tires on Road helps improve.
 

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ChrisNLA

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I average 16.5 or so with a lot of short city driving to work. 18.3 going back and forth to our other house, which is 35 miles of 55-65 MPH with some red lights, or cruising on the interstate at 67-68MPH.

Much over 70 the MPG goes out the window.

Also all the ground is flat here.

Im on 33s with the front end leveled out and the factory front bumper skid missing, so I didnt do it any favors on aero.

These suck on fuel.
 

Dilly’S Willy

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My 21 Willys with the dreaded manual and 3.73s and 32" MTs was getting around 17-21mpg avg in the summer, but with this shitty winter fuel I'm lucky to break 16mpg and closer to 14-15mpg avg. I'm mostly in 55+ areas with large/long hills from a slow start. I can't wait for better weather again, doors/top off, better mpg, just relaxing.

Check your tire pressures too. Mine were about 44psi in the summer and it drove like crap and lowering psi actually gained 1mpg avg everywhere and drove better. Similar in winter, tires went to 33psi and I went back up to 36-37psi and gained that 1mpg from 12-13.

It's just a box, with big heavy tires and you need to rev it out when you want power. I noticed when trying to keep rpms below 3k and going up hills or passing at speed would TANK my mpg. For city driving when you don't need to get up to speed, let the auto do it's thing and be easy on the gas pedal. When you need power, try manually shifting to stay in the power band when you need it and going back when done.
 

camss69

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I’m still stock as far as drivetrain, suspension and on the stock 33’s but live in a very hilly area and I’m only getting mid 14’s. When I’m down in the valley it gets quite a bit better but the downhills definitely do not cancel out the up as far as MPG is concerned lol.
 

Dilly’S Willy

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I’m still stock as far as drivetrain, suspension and on the stock 33’s but live in a very hilly area and I’m only getting mid 14’s. When I’m down in the valley it gets quite a bit better but the downhills definitely do not cancel out the up as far as MPG is concerned lol.
It's winter blend fuel currently, so you're getting the same mpgs I am in a similar environment.
 

NC_Overland

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Mine didn’t start getting the EPA MPG till about 15k miles. These engines take a long time to fully break in.
 

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Dilly’S Willy

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Mine didn’t start getting the EPA MPG till about 15k miles. These engines take a long time to fully break in.
At 40k miles currently, from 28k in August. And it's more the ECM learning your driving habits/fuel quality/etc during that time. Do a firmware reset/reflash without saving any current data points (like when new) and watch it be weird again. Something we learned in school, and in the field.
 

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Verne

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1) Engine break in
2) Check tire inflation. Bump it up a tad if you are a highway only driver.
3) You are driving a box into the wind. There is a stretch of highway that I use (70mph posted) where it is completely flat and nothing but fields. When driving west at speed, my mpg is horrific.
 

Trollboogie

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I will say my 24 Mojave with KO2's gets about 2 miles per gallon less than my 21 Mojave with KO2's did. Both were exactly the same 35s, stock 4.10 gears and same route to work. The only different is my 24 has the 4 high auto and the factory steel bumpers. 18mpg on the 21 and 16ish on the 24. Maybe it could be the 21 was hydro blue and my 24 is black 🤔
 
 







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