ok so I have a 96 cherokee with 275/35/15 tires and no lift. I am figuring i am getting 12 miles to the gallon. So I am thinking i want to look at the plugs and or sensor. I dont know what else would cause this. I live in the midwest so I have been latly using 4x4 all the time would that lower it?also would the cold weather make the ecu dump more gas in then needed or is it only while engine
is cold?

 

O2 sensor

 

your gas mileage sounds right for using 4 wheel drive all the time.

check your codes to see if anything is misreading.

 

what the heck?! that is soo off the wall and doesn't help anyone.

to the OP: I'd say that it could be a combination of using 4x4 alot and the cold weather. Cars tend to use more gas in cold and 4wd burns more gas than 2wd. Wait till you can use 2wd for most of a tank and see if your milage goes back up, I'd expect that you'd see high teens using 2wd all the time.

 

I just posted this in another MPG thread yesterday, so I thought if its ok I would copy it here:

Here is a link to a fuel economy site, that shows your ACTUAL mileage per gallon, which is correct as far as I can see because I checked it with my vehicles, not the EPA mileage, which is higher.

Example, My '97 with 4.0 auto and 4WD shows 13 city, 18 hiway, with a combined average of 15mpg, (hiway/city).....ouch.

Click on this link: http://www.fueleconomy.gov/

on upper left, find a car, follow the links, if you click on your model, you will get your combined and other info including the EPA version.

This was the site that the dealers used for cash for clunkers.

 

Actually I gained a few MPG when I changed my downstream o2 sensor

 

downstream o2...would this be the one closest to the engine or farther down the exhaust ...?

 

All this fuss about MPG. I get 12 mpg and I'm just happy to see double-digits gas mileage. My last truck was a 1989 2wd Dodge Dakota, which I found out had no overdrive after purchasing it...It had no power, was slow, couldn't do a burnout in the dry and got 8 MPG. When I bought my Jeep I was so happy to see 12 mpg.

 

Between the cat and the muffler

 

warning lights? any on? Check for codes if so.

engine coming to operating temp? This is important, cause if not, computer dumps fuel to try to raise temp.

do the simple things: tire pressures, driving habits, fluids[i use synthetic's], air filter, etc.

How does it run/start?

I run Quaker state synthetic all year, plus the diffs have Mobil 1, ease of starting plus, this Jeep rolls down the road, instead of being pushed. 80w90 gear oil does not like to move to easily when cold. Synthetic oils in diffs can increase mpg from .5 to 1.0mpg, does not sounds like a lot, but over a year of driving?? you firgure it out.

 

I get roughly 16mpg in 4wd all the time. My Jeep has 130 km on it though (or 80,000) miles. Jeep failed its e test though so i replaced both O2 sensors after I used a scanner to confirm the downstream signal was not present and the front one was slow to react. made a huge difference

 

I thought its was low but I am glad at least its normal for a cherokee to do that in 4x4