Is something wrong here?

[scull20]

Ok well since I've gotten the Liberty I have not been doing much "city driving" just highway going back and forth from home to school. Well now that I'm home I started working again doing food deliveries...all "city driving". I do my fair share of stop and go but I also do my fair share of just chuggin along around doin 30-45 as well. This past week on any given day the EVIC was saying that I was getting anywhere between 12-13 MPG.

This seemed a bit off to me so I went to fill my tank before work. Reset my trip miles...and after work I headed back to the same gas station to top off my tank to see how many gallons I used. 2.99 gallons in 36.8 miles...12.3 MPG .
My Dads Silverado gets better city mileage than that. I do not drive aggressive and I've recently changed the air filter and gotten and oil change.

Are my new wheels and tire really whats to blame for my terrible mileage?

Thanks for the help!

-Ryan

 

[VTNomad]

MPG's

What sizes tire are you using? Those can throw of the odometer, miles and mileage. How many miles do you have? May be time to change the spark plugs. Check your air filter as well. I had mice build a nest in my Explorer's air box one year, my mileage plummeted.

I'm getting 16-17 areound town and 21-22 on the highway, and have been since day 1.

 

[t2raz]

I get 14MPG on city driving and 17 Highway

 

[scull20]

245 70 16 tire, Airbox is clean and filter is changed, 60k miles

 

[tjkj2002]

Sounds normal to me,I get about 10-12mpg city driving,19mpg highway.

Those bigger tires and MOAB rims is to blame.

 

[scull20]

I kinda figured that, thanks for the clarification

 

[ripper42]

12-13 city 17-18 highway those tires are what kill you mpg. but let just all face it we do not drive jeep to get mpg we drive jeep to perform were the road ends.

 

[tjkj2002]

12-13 city 17-18 highway those tires are what kill you mpg. but let just all face it we do not drive jeep to get mpg we drive jeep to perform were the road ends.

AMEN!!!!!!!!!!!!!!!!!!!!!

If you want good mpg's a Jeep is not what you want,if you want a Jeep don't expect good mpg's.

 

[kjfan18]

Dang Those numbers make me feel good. I get about 18mpg on average in the city and about 21 highway in my kj.

 

[Marlon_JB2]

Tune Up.
Make sure tires are inflated properly. I found my Toyo Open Country A/Ts in 245/70R16 liked to be at 38-40PSI.
Check air filter
Keep under 3000 RPM, as low under that as you can. I find that for City driving, the Liberty has enough torque that 2500 RPM is fine. (This is subjective though, depends on how you want to drive.)

There's not much else you can do. It's a Jeep.

 

[sevenhelmet]

My mileage dropped a little after I put on my Soft 8s and slightly heavier tires. Making the spinny things heavier adds a lot to your vehicle's inertia (think about how much effort it takes to spin a wheel that weighs 40 lbs plus the weight of the tire!) Per pound, heavier wheels/tires has a MUCH bigger effect on mileage than payload (e.g. what you're carrying.)

But still, 12 MPG seems little low for what you have. Check your engine out just to make sure you're not missing anything. Could be time for new sparkies or something.

 

[J-Thompson]

I am going to go with something is wrong
we have an '03 ,OME, 245/75 MTR's and get 14-15 city and 20+ highway
with 55K on it
Our tires are bigger and heavier so I am guessing that is not your problem
improper PSI in your tires could be an issue probably not
when was your last tune up ,plugs changed?
IIRC they should be changed every 30 or 36K
also fuel filter? do you have a light bar or roof basket?
Things like that "drink gas"

 

[JeepJeepster]

Ive never gotten 12mpg in my Jeep. In the city I know I do not get under 14-15mpg, evic usually says around 15-16 or so with pure city driving.

On the hw it really varies depending on the terrain and driving habits. Anywhere from 16-19 or is usually what I see on the hw.

I would say if I went back and found all my posts where I post my mpg they would all be different.

I do exactly what marlon said. I try my best to keep it under 3k rpms when driving on the hw with a few 3500rpm downs shifts and accelerations. I almost always keep it <2500rpms with pure city driving.

 

[tjkj2002]

Ive never gotten 12mpg in my Jeep. In the city I know I do not get under 14-15mpg, evic usually says around 15-16 or so with pure city driving.

On the hw it really varies depending on the terrain and driving habits. Anywhere from 16-19 or is usually what I see on the hw.

I would say if I went back and found all my posts where I post my mpg they would all be different.

I do exactly what marlon said. I try my best to keep it under 3k rpms when driving on the hw with a few 3500rpm downs shifts and accelerations. I almost always keep it <2500rpms with pure city driving.

To bad you could never possibly keep the rpm's under 2500 where I live,it would take you about 20 miles to get to 25mph that way and would get run off the road,it seems to be all up hill.I try to keep it under 5500rpm's.

Terrian,driving style,gas,maintance,extra weight(skids,bigger tires,rock rails),lifted,and weather all effect mpg's so everyone will get different mpg's even if all driving the same type of vehicle.

 

[JeepJeepster]

To bad you could never possibly keep the rpm's under 2500 where I live,it would take you about 20 miles to get to 25mph that way and would get run off the road,it seems to be all up hill.I try to keep it under 5500rpm's

Yea, I can see where trying to keep the rpms that low wouldnt be practical for some people given where they live. Some people live where its totally flat so they dont understand what we mean by 'hills and mountains.'

 

[vaughan1966]

I kinda figured that, thanks for the clarification

what your wheels back !!

 

[jnaut]

I kinda figured that, thanks for the clarification

Is your pinion factor set properly in the computer? While bigger tires will downgrade your mpg performance, it may not actually be that bad.

 

[scull20]

what your wheels back !!

Thats ok, I'll pay the extra gas

I got a 15 average today driving around. It was probably just busier than I realized the other day at work so I was driving more aggressively.

-Ryan

 

[indieaz]

Wife and I generallly got 18mpg city and 24 highway the first 1.5 years of ownership. However, in the last 6-9 months mileage has slowly been dropping. We are now seeing 16mpg city and 20-21 highway. not sure what's gonig on, air filter is nice and clean, tires are @ 40psi (we changed the tires, but still on OEM rims and tires are street tires). It doesn't seem right to me. I have a feeling we have an O2 sensor maybe that's reading lean, but no way to check it really.

Vehicle is just about to turn 30k miles. We've also known it idling a bit rough and shuddering a tad when idling in drive. I hate to just drop a bunch of money swapping the plugs and wires and O2 sensors. I wonder if the dealer would consider it a warranty issue? I have a feeling the answer would be no.

 

[Marlon_JB2]

There's no wires to swap. Just buy plugs. Of course I'm sure you knew that and it just traditionally came out of your fingers.

The stock NGK plugs are worthless IMO after 20,000 miles. I've changed them on 2 3.7Ls and at about 20k, that's when mileage, performance and smoothness starts going downhill. I can tell when KJs need tune ups at work, they run horribly.