Long story short, my fiancee purchased a 2007 Jeep Liberty Sport (4WD) yesterday. Initially I thought we agreed a Jeep Compass was a better option for her because of the improved gas mileage and plus she really didnt need the size of the Liberty. Well...she got the Liberty and now I am looking to Texags to help me improve on the gas mileage I soon have to be paying for.

First and formost I am not a "car guy" I am engineer great with tools so long as there are instruction to go along with my car tinkering, but I have limited car knowledge.

I have done some research and came across a throttle body spacer http://www.airaid.com/ProductDetail.aspx?ProductID=310-618 which is said to improve up to 4mpg.

Also I have seen that upgrading to some quality spark plugs may get some better performance.

Are these minor fixes worth it? Do they actually work? Any other non expensive ideas?

Be careful with some of those things because they might mess-up a warranty...

jet,

"spacers" do squat. Plugs might help a LITTLE. If it's not too difficult (as in having to jack up and remove a wheel, etc.), then it's a fairly low-cost "mod" that you can attempt and if it's not effectual, meh.


You can tune it with a handheld, or PC with tuning software, but like mentioned, it might void any warranty to the drivetrain/engine.

I'm sure you know that the Liberty is known to be thirsty for its size. The 3.7L engine is a very unimpressive design - only 210 hp when Honda, Toyota, Ford, etc. get at least 240 hp out of 3.5L and better mileage.

Sorry I couldn't help it.

I have read that throttle body spacers are a proven improvement for Nissan 350Zs. But I would not buy one for the Liberty unless you have a sound recommendation for it. This wiki article claims TB spacers should be avoided because they do absolutely nothing.

I doubt spark plugs will help .05%. If they did, Jeep would have used them.

The problem with so many fuel economy add-ons is that you spend money, gain little or nothing, and it ends up as money that could have been used to buy fuel.

Did she need 4x4? That alone probably cost 2 MPG.

When it comes time to replace the tires - consider tires that are known to have less rolling resistance. Impressive offroad tires are poor rolling on asphalt. Consumer Reports just tested SUV tires and that is one of the things they test. Keep the tires inflated properly.

Consider using synthetic oil - it may help slightly.

Thanks for the input everyone, I was afraid that all changes were going to be so minor it might not make a difference.

As for why she got the car. We are getting married in January and her dad thought it would be a good idea to replace her 1999 Mercury Cougar that was falling apart and about to be a maintenance nightmare and burden on our future finances. As a wedding/christmas gift to her he offered to buy her a new/used car.

The 4WD was a nice option for us because we do some remote hiking in Arizona and some of the washed out roads can be sketchy...especially in my Jetta. I am fairly certain however that the Liberty she got is 2WD until it engages to 4WD because of slippage or I manually force into 4WD Low.

I am working out of state and I was home last weekend and we spent the time at car dealerships. I though I convinced her that a Jeep Compass with 28 MPG was going to be a better option. Yesterday her dad and her went shopping and came across the 2007 Liberty with 25k miles and got it down to $13k out the door.

It is a very nice gesture from her dad to give her/us a new car without the maintenance issues, but I wish it was more economical. I am assuming we will be driving my car more often unless hauling thing around or taking it out in the remote/snowy areas of Arizona.

convince her to accelerate slowly and keep it under 65 on the freeway. you'll make more of an impact changing your driving style than you would with "add ons"

course, if you couldn't convince her NOT to buy the liberty, you might have a hard time doing that (sorry, couldn't resist)

Well, the good thing is it's a free ride.

Therefore, no matter how craptastic the mpg is (probably high teens), it's still better than 28mpg AND a car payment.

jets - It is great to get a free vehicle - even if you didn't get to pick it. If you need 4x4 - you gotta get it. One thing the reports say is that the Liberty is very good offroad.

Be careful with spending $$ for add-ons for fuel economy. The vast majority don't work at all. Some of the ones that do - cost $$ and you have consider whether you will achieve ROI.

Improved the gas mileage on my wife's '05 Liberty from a dismal 19 mpg to an outstanding 37 mpg.

How did I do it you may ask?


I traded it in on a hyundai accent.

Gotta go with what sts said before - changing driving behavior. That will be the single biggest factor on fuel economy. Accelerating slowly, slowing gradually, and driving the speed limit on the highway will be the things that make the most difference.

Also, tell her to get rid of any unnecessary junk in the back of the vehicle. Every extra pound of unnecessary weight leads to incrementally lower fuel economy.

Just my 2c.

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Consider using synthetic oil - it may help slightly.

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This would be my suggestion. I switched to Mobile 1 in my truck ('07 Frontier CC) and went from about 325 miles per tank to about 370, and my driving habits haven't changed a bit. I know it sounds like it's not happening, but I reset the trip odometer everytime I fill up and would have the light come on about 310 miles. Now, it doesn't come on until about 350.

You can change the oil yourself using Mobile 1 (or another good synthetic) for what you'd pay for some Jiffy Lube place to put in crappy oil.

As others have said save your money on the add-ons, and focus on driving habit and proper maintenance.
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You'll be happy with the vehicle on the light duty 4X4 trails though.

I believe you have the Selec-Trac II system, but I could be wrong.


[This message has been edited by p_bubel (edited 11/18/2008 3:37p).]

I typically put synthetic into my vehicle and do notice a slight increase as well. I will be sure that she does the same. Thanks for the replies everyone.

I am happy we got the car for free. Next time I will make sure she will obey me (just dont tell her I said that )

[This message has been edited by jetescamilla (edited 11/18/2008 3:38p).]

Hey, I put Mobil 1 in my Mustang tank and I drive conservatively, but I only get 17 in the city and 22 hwy. I get an average of 20 mpg per tank and can go about 270 miles per tank if I'm lucky.

During the summer when I interned at a law firm just 1.5 miles from my house, I would only get about 16 mpg on a tank, but it would be ALL city. A tank would still last me a month, but still.

Dang, helgs. You have a v6 Stang to boot.

My 2004 GT Convertible got better than yours is. Well, city was about the same, but hwy I got 22/23.

Traded mine, one of the best moves ever.

I miss the Libby but not the MPG...

Rob, I have true dual exhaust (with a GT bumper). That's where I think my mileage went.

Are K&N drop in filters or Fram AirHogs not worth any improvement? I figured they weren't, except that they save you money in replacing filters so often.

helgs, I get 17.8 MPG out of my 5.4L F-150 supercrew.

K&N drop in filters or Fram AirHogs may or may not give you a 1 MPG improvement.

I said may...

I use an Air Hawg in my Chevy and it gives about that in my F150 no improvment.

can't spell Hog twice in a row.

Keep in mind, if any of these add-ons added nearly as much MPG as they say they do, they'd be used by the auto manufacturers.

Accelerate slowly and keep highway speed between 60-65. That's how I got my mpg in my '07 Silverado up to about 20.3. Of course, now that gas is cheap again, I drive like a crazy idiot once more.

best way to improve mileage?

tow it

I would recommend upgrading to a good synthetic oil, such as Mobil 1 or Royal Purple. A computer "tune" is your best bet as far as increasing MPG. I wouldn't really worry about it too much, though. A new free vehicle is a new free vehicle. I'd be happy.

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I am fairly certain however that the Liberty she got is 2WD until it engages to 4WD because of slippage or I manually force into 4WD Low.

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This doesn't matter to gas mileage. Any 4x4 system whether part time or full time is going to lower mileage due to the weight of the system, extra moving parts, etc.

Don't drive.

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Keep in mind, if any of these add-ons added nearly as much MPG as they say they do, they'd be used by the auto manufacturers.

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I beg to differ with this mindset, though I hear it often enough:

"If </insert non-OEM part here> were really that great, </insert auto manufacturer here> would put it in there to begin with."

If they did that, then every car would be $100k or more. What they DO do is design a car that has certain bells and whistles, usually, all of those bells and whistles are mediocre when compared to aftermarket, but they're designed together at a certain pricepoint.

Take stereos, for example, save for a certain few exotics, most OEM systems suck. A properly designed aftermarket system would kick any OEM (save for the aforementioned exotics') system in its nads and spit on it. But, it would cost a lot more than most are willing to spend on "sound", so they put in their crappy system and go with that.

The same can be said with a vehicle's ECM tune. It's set for optimum MPG for a certain situation. Stray from situation and it'll get worse. I've gained several MPG via tuning my own computer in the TBSS. EPA lists 13/17, I get 14/20 now. The stock tune doesn't lock the tq converter, which gains a little, nor does it account for different "air".

I understand your point, but a throttle body spacer? Cost on those things is probably in the pennies. Cost on K&N air filters (at GM's economy of scale) would probably be around 50 cents. If it helped increase any amount of MPG, they'd have them on there. Stereos are much different.

Well, spacers don't do squat. I've personally tested K&N filters with before and after performance tests. They work (not necessarily MPG). On those, they make more money by selling them as aftermarket parts than they would by adding them to the vehicle.

Carpool

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I've personally tested K&N filters with before and after performance tests. They work (not necessarily MPG).

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so does just taking the filter off, but that's not a good idea either...

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Funny thing is it just might not run. They are tuned for the pressure drop that occurs not only over the air filter but also through the whole intake system. Decrease that pressure drop and it just wont run.

Well unless you reprogram the computer to richen up the mix.

Trade it in for Honda CRV or Element!

I get 24mpg on HWY!!