leo3000

im at half tank right now and ive gone 65miles. thats terrible.

what could be the cause? i do have an evap sys leak, and i sometimes get a rough idle after comming off the interstate. could it be an o2 sensor?

thanks alot
-Leo

(jeep specs are in my sig...)

96Cherokee113

Has it always been that bad, or is it just recently? Have you been using 4x4, been heavy on the gas, or letting it idle for long periods of time due to the snow and cold weather? It could be a number of things, really. We need more info to try and figure it out. For example, did this occur out of the blue, or did you do something to the Jeep and then this happened? I got my Jeep in October and calculated that I get 12 MPG. I changed plugs, wires, cap, rotor, CPS, O2 sensors, and eventually put in another distributor when mine crapped out and I still get 12 MPG and it's nearly stock. I can live with it, though.

Tural

something is definitely wrong. my 99 gets 22-23 highway, 14-17 city.

Tural

first of all, do a little experiment. take an interstate trip. drive 55, but give just enough gas to barely move forward. i drive like a grandpa and am known for getting above average mileage out of anything i drive. i don't even accelerate to 55 too fast. an i6 has enough power to pick up good speed even at idle.

leo3000

i dont know if i have that kina patience, and i dont have anywhere to go, and thats a pretty expensive experiment, but... i geuss 8 mpg is gunna get pretty expensive too...

RedZeppelinXJ

i'd start out with running some seafoam through that thing....you would be surprised with the amount of garf you will see burning out of your engine....me and my brother do it to our cherokees every 6 months or so and you can really feel the difference afterwards....i would also check your plugs, plug wires, and distributor.....my XJ gets about 21mpg highway so 8 seems really bad

blkcherokee

i know the feeling man mine just started doing that to me today i have replaced both O2s an my cat..... now i am working on the cap, rotor, plugs, an wires if that idk i am lost to its getting anoying i drive 60+ miles to work an back so i feel ya.... i sputter a lil bit at first then she runs fine an then after sitting at a light my idle gets really rought.... i am so lost at this point

leo3000

maybee my odometer is messed up... that would be great... i can try tracking it w/ the gps

Chrkee313

If you have an evaps system leak then most likely its gonna be your gas cap, but check for broken/disconnected lines coming from the charcol cannister.

To blkcherokee: try cleaning your idle air control sensor on your throttle body and check for signs of vacuum leaks.

greengoblin

bump

miethead

I get horrible miliage too, worse then my 96 ram with a 5.9L v8 4x4 with no exhaust. Mine dropped way down when I put the 33x12.5's on it, lot more rolling resistance, also have them aired down to wear more even. Thing that bugs me is that when I am going 55 if i go up a hill it has to rev to like 3000 to keep speed. also on the freeway to do 65 or 70 its at like 2500, which is also hurting my mpg

84supersport

Now that it's winter whats your running temp. The previous owner put a 160 degree t-stat in mine to fight the common summer traffic overheating problems but when I bought it before winter it would only run at 160. I got 9mpg since the computer was running it in choke mode all the time. Putting a piece of cardboard in front of the radiator got it to run up to temp until I had a nice enough day to change it. Now I'm back up to my normal all around 14mpg. That's with the odometer be uncorrected for my 31's so I don't know how much that would affect it.

red97cherokeewithsunroof

definitely replace O2 sensor and TPS and MAF. you will get way smoother idling and better MPGs i promise. also replace ignition coil. probably stick with OEM from autozone for now, but it helps idling and take off.
also, the higher octane gas is better for your car. everyone uses the cheap 87 (or whatever the lowest is at shell) octane but i use the 92 (or whatever the highest is at shell). yes its $4 more to fill up but it does show better gas mileage and smoother ride
X2 on sea-fome. it works wonders.

tjwalker

Do the math folks if you want accurate gas mileage data.

Miles driven divided by gallons consumed. Takes all of 30 seconds when you fill gas.

Extrapolating your mileage by the amount of miles per tank is not particularly accurate.

Get at LEAST three samples before making any assumptions. Too many variables to come to any kind of conclusion with 1 sample!