Improving gas mileage

[mindbomb]

I'm getting anywhere between 12-14mpg combined with my stock 03' KJ which is similar mileage people/friends are getting from their:
- Wrangler with 35"s (actually 15-17)
- Ford F-350 6.4L
- Dodge Charger HEMI V8
Etc you get the idea

All filters and fluids were replaced recently and I added techron fuel system cleaner to the tank few tanks ago.

Any idea how can this be improved?

Thanks




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[LibertyTC]

Ya Jeep is a brick so mileage depends a lot on how one drives, and city mileage is a killer. However you can try to remove all unnecessary weight.
New OEM spark plugs. Any engine codes present?
Rear diff lube new helps. Synthetic engine oil?
Clean throttle body, IAC/ports and make sure PCV is clean/no gunk in filler tube?
This was my original sticker:
56067[/ATTACH]"]

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My Jeep is lifted it takes me camping in style and sometimes it is best just to accept that it is A...
56069[/ATTACH]"]

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:gr_grin:

 

[teeje]

Smiles per gallon


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[ozone000]

Of course those numbers are imperial gallons, so they translate to 16 city and 23 highway (rounding down for both).


The most effective improvement for mpg is to adjust the nut behind the wheel. If you don't know what adjustments to make, go to 100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com. Any other adjustment to the actual vehicle are suggested at 65+ Vehicle modifications for better fuel economy - EcoModder.com



If those are too long to read, here is the rule of thumb: Idling is bad. Driving below 30 is bad. Driving above 55 is bad. Using brakes is bad. Being in front of a line of cars is bad. Automatic transmission kickdowns are bad. There isn't much else you can control.

As for comparing MPG between vehicles, you really need to have more info than you presented. The year of vehicle will make some difference, as will their driving habits/environment. For instance, I can easily get 50 mpg on my Triumph during my commute, but I generally get 42 because the mileage hit is worth not getting run over by cars doing 85 in a 65 while I'm doing 55. If you live close to work and your friend lives far away from work, your friend will get better mileage, but you will use less gas.

 

[CzarKJ]

Of course those numbers are imperial gallons, so they translate to 16 city and 23 highway (rounding down for both).


The most effective improvement for mpg is to adjust the nut behind the wheel. If you don't know what adjustments to make, go to 100+ Hypermiling / ecodriving tips & tactics for better mpg - EcoModder.com. Any other adjustment to the actual vehicle are suggested at 65+ Vehicle modifications for better fuel economy - EcoModder.com



If those are too long to read, here is the rule of thumb: Idling is bad. Driving below 30 is bad. Driving above 55 is bad. Using brakes is bad. Being in front of a line of cars is bad. Automatic transmission kickdowns are bad. There isn't much else you can control.

As for comparing MPG between vehicles, you really need to have more info than you presented. The year of vehicle will make some difference, as will their driving habits/environment. For instance, I can easily get 50 mpg on my Triumph during my commute, but I generally get 42 because the mileage hit is worth not getting run over by cars doing 85 in a 65 while I'm doing 55. If you live close to work and your friend lives far away from work, your friend will get better mileage, but you will use less gas.

Cost me $6 bucks to go 100 miles on my triumph last thursday. And that was expensive due to my spirited riding!

To the OP. Clean EVERYTHING. As libertytc said throttle body cleaning and new copper plugs does wonders. Other than that it's a toolshed in a hurricane...

 

[Dave]

Yeah, the KJ is a un-aerodynamic 4,200ib brick. It is too high off the ground and the tires are too big. A real pig. But more fun than a little itty-bitty pos econobox that weighs half as much and sits way too low to the ground and has teeny-weeny tires and gets stuck on wet spots.......LOL


Dave

 

[tommudd]

Open hiway 21 to 22 with my 04 lifted regeared etc, the 03 only a baby lift at 2.5 inches of lift and 265 70 16s havent regeared yet but got 17.75 pulling a 6 x10 enclosed trailer with OD off and running 75 plus, havent checked it on the road without trailer yet since lift

 

[CactusJacked]

I get in the mid 15's combined and in the 19's straight highway. I found one contributing factor is whether or not I leave my lead lined right shoe at home.

 

[teeje]

Got 25.7 on my way home. 45 minute drive with a couple stop lights and city driving (country roads)


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[HoosierJeeper]

I get about 13-15 in the city, that's with lots of idling and a leadfoot.

On county/state highways I get about 20-22 depending on winds, on the interstates going 80 I get about 18.

 

[dude1116]

Got 25.7 on my way home. 45 minute drive with a couple stop lights and city driving (country roads)


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I just don't see how this is possible with the 3.7. Best I could squeak out was 23 with stock tires and that was driving like a saint. Then again a 45 minute drive does not make a good benchmark for average MPGs

 

[teeje]

I just don't see how this is possible with the 3.7. Best I could squeak out was 23 with stock tires and that was driving like a saint. Then again a 45 minute drive does not make a good benchmark for average MPGs

It's possible when me engine is a reman with only 9,000 miles on it and clean throttle body and IAC and good gas and cruise control. Average for a week if I keep my lead boot off is about 20-22 mpg for city and highway driving altogether.

 

[uss2defiant]

buy a car

 

[JasonJ]

Good fuel mileage is not why I bought my Jeep... but that is besides the point.

I get 17mpg combined city/hiway in the winter, 19mpg summer. Highway at 70mph, cruise activated, 20-21mpg. Drop that down to rural two-lane highway at 55mph, and I can pull 24-27mpg (yes, I said 27MPG) in the SUMMER.

I just towed a dead 2001 Tahoe 45 miles with my Liberty, despite being about 1500lbs over my towing limit, I still got 19mpg and that was with O/D off.

Change all fluids that can be changed.. that includes the differentials. Use of synthetic fluids helps. But, not knowing how you drive, but knowing how most other drivers around me drive, assuming it's the same, the biggest factor in MPG is YOU.

Coast to yellow or red lights.. why do you need to be maintaining speed towards a stop? Don't do your best 0-30 or 0-60mph runs when the light turns green... dont accelerate like a mule, but there is no need to rev it up to 4k RPM either.. in fact, I rarely go over 2500-3k rpm under normal acceleration.

Make sure your tires are inflated properly as well, and have good tread. Low, worn, or uneven tire tread can introduce another source of friction between the tires and the road.. and that counts too.

 

[CalcityRenegade]

I averaged 13-15 mpg city (Some highway) driving with my KJ. I get 12-16 mpg with my crew cab 4WD V8 Titan with LT33x11R20's and the big tow package. This is why it made no sense to keep the Jeep. I do miss driving it though.

 

[mindbomb]

Hey! Good advice. Thanks!

I got worn tires (that'll be replaced soon), that might also contribute to the bad mileage I'm getting. Assuming rear/front diff lubes were never replaced since 2003 - that should be relatively easy.

I am new to many of these terms.
Can you explain about : IAC/ports, PCV, filler tube? not sure what/where they are.

Ya Jeep is a brick so mileage depends a lot on how one drives, and city mileage is a killer. However you can try to remove all unnecessary weight.
New OEM spark plugs. Any engine codes present?
Rear diff lube new helps. Synthetic engine oil?
Clean throttle body, IAC/ports and make sure PCV is clean/no gunk in filler tube?
This was my original sticker:
56071[/ATTACH]"]

You must be registered for see images attach

My Jeep is lifted it takes me camping in style and sometimes it is best just to accept that it is A...
56073[/ATTACH]"]

You must be registered for see images attach

:gr_grin:

 

[tjkj2002]

I just don't see how this is possible with the 3.7. Best I could squeak out was 23 with stock tires and that was driving like a saint. Then again a 45 minute drive does not make a good benchmark for average MPGs

I got 21.9mpg's with my KJ when it was still IFS with 265/75R16's(load range D MT's,and 4.10 gears) doing 78mph on I-70 going to MOAB(so way from flat and high altitude),not to mention at the time my KJ weighed 5500lbs before my fat butt and a weeks worth of gear and spares for MOAB.


And now I get maybe 7mpg in town and can best 18mpg's highway with my KJ.

 

[dude1116]

I got 21.9mpg's with my KJ when it was still IFS with 265/75R16's(load range D MT's,and 4.10 gears) doing 78mph on I-70 going to MOAB(so way from flat and high altitude),not to mention at the time my KJ weighed 5500lbs before my fat butt and a weeks worth of gear and spares for MOAB.


And now I get maybe 7mpg in town and can best 18mpg's highway with my KJ.

The 4.10s is the difference here. If i had 4.10s I'd be back to getting 22-23 MPG highway...but I still can't see 26.

 

[ltd02]

I just put more gas in it when it gets low. I don't really pay much attention anymore now that it isn't 4 bucks a gallon. I fill up once a week and that's okay with me. It ain't a Prius (thank God!).

 

[teeje]

Always a good idea to get her up in the higher rpms once in a while too (no I don't mean rev in neutral) get a long not busy back road and let her rip


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