13mpg normal?

So I bought a liberty with 160,000 miles on it. I tested the gas mileage with mixed driving. The first tank, I drove normal, allowing shifts around 3000 rpms. I got 13.5 mpg. The next tank I kept off the gas a little and didn't let it get over 2000 rpm. I still got 13.5 mpg in similar driving situations. Is there something wrong with my Liberty. I would have expected to get atleast 17 or so in mixed driving, especially keeping my foot soft. I realize its not going to be great, but 13 is pretty terrible. I don't know if my liberty has ever had a major tune up either. Would this be the problem? What all should I get tuned up on it if it needs it? Also I upgraded to 245/70/R16 tires.

You sort of answered your own question right there.
If you don't know anything about whats been done maintenance wise then I would start with a good tuneup, change the oil, transfer case, diffs etc
Make sure its running right before you complain about mileage
Also winter time is not the best time to try and determine gas mileage

Yeah, what Tom said!
We're getting about 16-19 mpg combined city/highway.
And that's with 245-75's with 4:10 gearing, fresh tune up, engine oil/diff gear oil/transfer case oil/****** fluid, the works!
All depends on how we drive to though!

i get the same mileage (13.5 mpgs) with 245 75 16s, i do mostly city driving though and never go over 40 in the city and a little highway (10 miles a day) going to and from school, i did plugs, new fluid and filter in the ****** and new fluid in the tcase at 60000 miles and do my diffs every 12000, run good quality gas (sunoco 87) and i have a jug of lucas upper cylinder lubricant and fuel injector cleaner i run every 2 or 3 tanks in addition to bg 5K oil changes (they also add an injector cleaner), im startin to think it may be the ignition coils getting weak, not to mention running the 245 75s on 3.73s, im sure 4.10s make a world of difference, also be sure that your speedometer and odometer are giving you accurate readings, checked with the gps before the lift and tires i was running stock 235 70 16s and my speedo was off by about 5 % IIRC after i threw on the new tires its maybe 1.5% off

X2 on gearing and good running
Our '03 had the 45RFE ,lower first gear
And must have been a freak of nature
we would get 16-17 mixed driving
on 10 ply 245/75 MTR's and 3.73 gears
doing at or just below 70 we could squeez 20 mpg
Now just to brag
The VW has only 20 less HP and 30 or so less torque
doing 75-80 we get 27 mpg highway
Back down to 70 and it gets near 30
And driving in the Smokies is much less "scary" even
at much faster speeds
We always needed to be in full time 4wd with the KJ
the VW is FWD only and holds the road better

Keep in mind that the throttle body is opening quicker than you think because of the way it is cammed. Probably aggressive at the start.

moparman said:

Keep in mind that the throttle body is opening quicker than you think because of the way it is cammed. Probably aggressive at the start.

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And this is different on his KJ vs every other KJ?

I'm just gonna throw it out there that 3,000 RPM is probably a little too much to be getting optimal mileage. I try to keep it anywhere under 2,500 and it seems to work very well for me. Plus if it's mad cold by you, you might see that kind of mileage. I see about 14-15 with combined driving in sub-freezing temperatures. (Luckily, it's been mild here in jersey )

If i got 13.5 mpg's in my kj I would cry tears of joy...I haven't seen above 11.5 in a while and my poor mpg's isn't due to cold weather or being heavy on the gas. Its sad that my 86' mustang GT gets double my jeep and it has the 5.0L with 3.73's and its cammed and i drive it rather aggressive compared to the kj and yet i still see better gas mileage just makes me wonder what the hell is wrong with the jeep. Recently i pulled my boat down to the valley and back (450 mi) and got at the best 8 mpg given i drove 75-85 the whole time. I do all regulator maintenance and replace parts regularly to find my "mysterious problem".

J-Thompson said:

And this is different on his KJ vs every other KJ?

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No, same for everybody (and almost all vehicles) but some people get good MPG and some people don't. I think it is all in the right foot. Stabbing the gas and being on/off the pedal all of the time is what kills the mileage. KJs get around pretty good on what seems like 1/8 pedal. Think ahead and apply that 1/8 smoothly.

I have 120,000+ miles of gas purchases recorded and calculated in a book, worst 14.97 mpg., best 24.4... old plugs, new plugs, old oil, new oil, paper filter, K&N, dino or synth, none of that stuff has really mattered as much as driving conditions and fuel blends.

I'll add on here with my experience. I consider myself lucky as I've had an '03 and an '04 practically brand new. The '03 had 3000k on it when we got 'er and the '04 the same. (did I ever say I shop A LOT before I buy) anyway, the '03 got about 16.5 when we got it. The '04 got 18 dead on almost all the time. This is city driving with a medium amount of stop n go. It's my opinion, but I think the newer KJs with the 42rle get better mileage. right now with all my mods, I'm getting about 15. But that's the price you pay right? Just matters what you throw your money at.

moparman said:

No, same for everybody (and almost all vehicles) but some people get good MPG and some people don't. I think it is all in the right foot. Stabbing the gas and being on/off the pedal all of the time is what kills the mileage. KJs get around pretty good on what seems like 1/8 pedal. Think ahead and apply that 1/8 smoothly.

I have 120,000+ miles of gas purchases recorded and calculated in a book, worst 14.97 mpg., best 24.4... old plugs, new plugs, old oil, new oil, paper filter, K&N, dino or synth, none of that stuff has really mattered as much as driving conditions and fuel blends.

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So your "gingerly" driving returns an average of about
19-20 mpg
all stock?
We got about the same all stock and drove how we wanted
Lost 2 mpg maybe when we lifted and put on taller tires
Sorry folks if you are getting less than 15 mpg average
in a KJ you have issues
My 10+ year old TJ with a 3 speed trans 33's and 3.73's
returns a 15 mpg average

J-Thompson said:

So your "gingerly" driving returns an average of about
19-20 mpg
all stock?
We got about the same all stock and drove how we wanted
Lost 2 mpg maybe when we lifted and put on taller tires
Sorry folks if you are getting less than 15 mpg average
in a KJ you have issues
My 10+ year old TJ with a 3 speed trans 33's and 3.73's
returns a 15 mpg average

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I was going to say that, but decided to keep my butt out of the fire today.

I used to get 16-17 with my OME lift, dynomax cat-back and 245/75/16 Duratracs...but since throwing a roof rack on and the spare up top i am down to 13-14...aerodynamics is a b***h.

Long trips with mine the way it is ( little heavier than most ) still pulls 20-21 on the road and thats at 70,........ plus :Bye:
Around town I could give a crap about MPG :shrug::happy175::happy175:

I think mine just has a drinking problem lol...

Stock, with A/T tires, so far this winter I've gotten 15-16MPG with a good amount being highway.

Last week I tried going into grandma mode and didn't go past 65MPH, highest I saw was 18MPG.

We've seen up to 25 mpg on the highway in our 06 Sport 3.7/auto/4x4. Typical hwy mpg is probably closer to 22.

Driving habits make a huge difference. One person's "gentle driving" may be completely different than another's.

One other thought: on a higher-mileage vehicle, a lazy O2 sensor can hurt mileage. It may be switching slower than it should, but not yet bad enough to set a code. I change O2 sensors around 100k as PM. (You only need to change the upstream sensors.) That said, our Libby has 93k, and is still on the original O2 sensors.

Yeah 167,000 on 3 out of 4 of my sensors
some roots tore side 1 number 2 up some and had to replace it, others all stock

I tired the seafoam additive in this past tank and so far I'm at about 225miles with a quarter of a tank to go and id say its the best I've seen since 2009. But that's pure highway driving in " Grandma mode" driving at a slow steady pace of 65ish minimal traffic.

belvedere said:

We've seen up to 25 mpg on the highway in our 06 Sport 3.7/auto/4x4. Typical hwy mpg is probably closer to 22.

Driving habits make a huge difference. One person's "gentle driving" may be completely different than another's.

One other thought: on a higher-mileage vehicle, a lazy O2 sensor can hurt mileage. It may be switching slower than it should, but not yet bad enough to set a code. I change O2 sensors around 100k as PM. (You only need to change the upstream sensors.) That said, our Libby has 93k, and is still on the original O2 sensors.

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I honestly don't even see how that's possible. Are you just using an EVIC calculation?