I thought I'd get better milage

I know everyone is complaining about high gas prices, what is one to do, blah blah blah.!!!1 I just went and filled up my tank-$80. My xj is a '00 4.0 60k auto 231 with a re 2" bb and 235/70r16 tires. My last tank was 14.3 mpg. Why is my milage so bad? I mostly do 16 mile round trip to work on the highway doing about 65-70 mph. Jeep runs awesome and is not throwing any codes. Just trying to save some money as a college student. Oh, I recently did a tune-up, added a k&n intake, flowmaster exhaust, and got an alignment.

Drive like an old man....especially taking off from lights. Try to coast when you can rather than going from gas to brake to gas to brake (anticipate the light turning red, the idiot pulling out infront of you from the side street..etc etc).

Keeping it at 60-65 rather than my normal 70-75 and occasional 80 made a nice difference in my mpg's on the highway....went up from 18 to around 20.

When I drive how I normaly do I get 12-14mpg, when I drive like my mom and sister I get close 19mpg. Big differance. It saves me around 1 fill up a week, that translates to more beer money!

Try slowing down to about 60. I've found mine('00 4.0 auto) gets its best mileage at about 50mph. How fast is your engine turning at speed?

at the risk of upsetting a good thing... i'll mention that i don't understand how some cherokees get such bad mileage.
i've got a 99 5-speed and a 2000 automatic, both with over 110,000 miles and stock except for a K&N filter.
i do not drive 'slow'... but i'm not a leadfoot either.
i'm normally the first away from a stop light, but keep at the speed limit in the city.
i'm in salt lake, which is about 4,000 feet.
to work i drive city streets with a lot of stop lights and get 17mpg average in the 2000.
when i drive to colorado springs thru wyoming, i get about 25mpg to Rawlins, and then about 20mpg to Colorado Springs. and thats doing 80 with the A/C on. i lose a little bit if i open the window and stick out my elbow.
i use the middle grade gas, which is i think 87octane.
the 5speed gets around 1-2 mpg better than the auto.

i've tried 85 and 89 octane and didn't see any difference.
i don't think i've ever even replaced any sensors... just the plugs once or twice.

one time i tried to get the 'best' mpg i could on a trip between SLC and COS, but coasting down mountains, driving behind semi's for a while etc.. and got 28mpg for the trip.. but that was to much work to do again.

i've got a 91 wrangler also and i think it gets similar mpg.

so now watch my mpg drop now that i've posted it.

i would think anything less than 17 on the highway would indicate something needs to be fixed, unless you always drive uphill or something

All those are great things...I'm sure someone said to keep your tires inflated too.

I have a tiny leak in my left rear driver's side tire and my PSI was at 18!! Plus I was driving my age starting up fast at lights, etc.

So...I started to drive like my Grandma and kept my tires monitored and I went from 400km a tank to 500km+ a tank at the next fill up!

UNCC_99XJ said:

Drive like an old man....

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thats pretty much it right there. actual highway RPM at a sustained speed has less impact than you might think. acceleration is the killer. around town stop/go driving kills me and i tend to be the fastest one away from a green light. i get about 15 mpg around town but 19-20 on highway with the "summer gas" they send us here in new england. my friend gets a full 10% better economy from my rig when he uses it because he drives like a granny.. fuel cost has definatley slowed me down to 65 on the highway from my usual 75.

Weight reduction.

i have an 88. all stock

i drive like an old man in town and limit my dirving as much as possiable and i pull 18ish.

on the highway, set @ 60 i pull 24 on a really good day.

200XXX miles and still rockin.

i found that not being a lead foot and what not helped ALOT.

Oh, I forgot to add that I started to use my Cruise a lot more too.

Damn, I am jealous....]

I did my calculations today and came up with 14.22 as an average....

I think my Renix XJ has issues though....

It's bitchy on cold starts and has a slightly higher idle than it should.....

I think it's time to change the coolant temp sensor....

It's not fuel supply or TPS, CPS or MAP..............

I have 240k+ and cracked headers. Replacing them this weekend.

I haven't had my 2K/4.0 very long. It's not burning oil but the pressure is really low so a rebuild is in the works. That said, I was getting around 15 mpg average on a 18 mile round trip all highway at 60-75 mph. I watched an episode of Myth Busters that talked about drafting big rigs and decided to give it a shot. I sit behind them at about 100-150 feet and if nobody slides in between us, I can feel the engine not working so hard. My opinion is that if there is something crazy up ahead, I can still stop faster than the truck and he's going to clear the way for me. Still, I keep back a good distance and say a little prayer. The truckers also have to get a lot more mass moving so they tend to be much more stable on the throttle and accellerate down hills and slow going up. That helps me with no cruise control to keep her steady.

My mileage over the last week has gone to around 19-20 which ain't bad.

If I were to try to get the best mileage possible, I'd probably go to 75 series tires, replace the AC pump (makin a little sqeak) lower it about an inch or two (ick) and put lockout hubs on the front. Basically try to lower the resistance being applied to the engine outside of the the massive drag coefficient this little shoebox has.

I also find that the white color (though I don't really like it) does allow me to have the AC on much less than in previous cars which can't hurt.

yet another gas mileage thread... hehe

it's hard driving correctly with how much power off the line the 4.0 motor has. Even driving like my grandmother the past week, it's hard NOT to be the first one leaving a redlight. However, I did gain 2 mpg this week! That's driving my normal 50mi round trip with a lot of traffic lights, backroads, hills, etc. Went from 14 to 16mpg. vehicle specs in sig. not really built for gas mileage... I'm getting ready to put my stock tires back on. Just put the 31" mud tires back on for trail rides.

Gas mileage threads!!!1
By the way putting lockouts on the front axle is more costly then what you would save in gas. My 94 auto has never been better then 17-18 on the highway. I've spent my money on all the sensors and tune-up stuff. Heck I even put the lock outs on it. I noticed 1/2 mile to the gallon increase is all with the lock outs. It is stock as far as lift.

Things could be worse......

At the moment in the UK, it takes about $145 to fill my tank!

Steve

1999 ax15 4x4 with 160,000 miles i just drove it from south florida to wyoming and got on average 25 mpg at around 80mph (everything is bone stock down the to the tire size) keep in mind having the 5th gear and also at 80 im only pushing around 2300 rpms

I've started doing some of the hypermiling techniques and have so far managed to bump my mileage.......so long as I stay off the roads that have stoplights that can't seem to be the same color at the same time:bs:

Stevemedlock said:

Things could be worse......

At the moment in the UK, it takes about $145 to fill my tank!

Steve

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That sucks..........big time

jeez, that's more than barrel for right now. Although scooters and hybrids are starting to come off looking really nice.

I got a code reader from autozone, it found no codes. jeep runs like new, basically is(60k). Would a bad o2 sensor cause my poor gas milage and do they go bad without throwing a code? I believe that since it's a '00 I have 2 o2 sensors right? I got 17mpg round trip to tahoe in the winter, some of those miles include going slow in 4x4 on the snowy roads.:banghead: