fuel consumption

alright, ive spent the last while since i joined this awesome board lookin for information about my 1992 jeep cherokee laredo. it has the 4.0 aw4 and np242. everything works great, except i cant get more than 300 kms to my 66 dollar tank :dunno: . im pretty sure it should get more mileage than this, and ive been reading up about idle air controller cleaning, and ive tried searching numerous times for IAC, idle air, and almost anything else i can think of with no results. so anyway, heres the specifics:

1992 jeep cherokee laredo
4.0l, AW4, NP242
320,000 KMs

im changing my rear main seal this weekend, or maybe next, as well as my oil pan gasket (it started as just oil pan, but after reading, uh-oh). ill also be cleaning out my pan of sludge, if theres some, but lets face it, therell be some. the only other thing i can think of is that its burning very slight oil, i can smell it under the hood, but not at the exhaust, the exhaust just smells rich of fuel. help me this gas tank is killing me!!:scared:

Im getting about the same mileage out of mine, and everything is new / fixed etc. Runs fantastic right now.
Im in U.S. so i think your mileage is equivalent to about 190 miles per tank U.S. You have the 20 gallon tank right?

I have a tendicy to drive fast, so im on the pedal alot. Your driving habits definetly play a role. Plus right now winter gas sucks, and in the snow / slick conditions running 4wd doesnt help. The only other thing i contribute my mileage to is my Jeep running on the cool side. I am in closed loop, but i still only run at about the first line on the gauge for temp. I rarely get up too 210 right now, and thats only if the Jeep is running, i stop at a light, and i dont turn on my electric fan to low. (mechanical fan deleted... dual electric fans).

Lots of contributing factors here. The only other thing i would recommend changing that definetly effects gas mileage is the 02 Sensor.

Hope that helps

damn, i really thought id be getting better than that. hm. well, i guess its O2 sensor time, see if i can get this a little better. as well, should i bother to try to clean my IAC, or just replace it.

I've got a 95 4wd/242/4.0 automatic, 3" lift with 31" tires stock 3.55 gears, with 140K on it. My gas gage is off a bit to the low side. The low level fuel light comes on at about 200 miles. When it gets to 275 I start looking for a gas station. It has a 20 gal tank but when I fill it up I only put 16-17 gal in it so I still have a few gal left but I don't like to push it. It works out to 16 to 17 miles per gallon.

The IAC shouldnt have much to do with your gas mileage unless its getting stuck open causing a high idle condition. I wouldnt mess with that. Just make sure you have done all the normal "tune-up" stuff, and possibly replace the 02 sensor. Then, wait till summer, and see how your mileage is. You cant judge it during winter using 4wd sometimes, and getting crappy winter gas.

Many bad parts can hurt mileage. How is your engine running? Is the idle normal? How does it shift? Does it have good power? What problems or oddities have you noticed?????

Stock you should be able to get 20 plus MPG on a long flat highway run. With stops signs every block doing 0-30 mph or in heavy traffic it can get as bad 10 mpg with a properly tuned, working stock XJ. Sorry you will need to convert that to KPH.

I did a lot of needed tune up work on my junker purchase, 87, 4x4, bought it 3 years ago, put in new fuel injectors, plugs, wires, cap, rotor, some sensors, radiator, fan clutch, alternator, battery, ICM, HV coil, distributor, MAP, IAC, MAT, ignition switch, and on and on, ..... they all helped fix numerous power and idle problems, but when it was all said and done they had no real effect on my mileage, the three most important items that got my mileage to double back to OEM specs was a new TPS, a new O2 sensor, and several new ground wires including the TPS sensor ground wires. The 92 may not be as prone to ground wire problems as the 87-90 models were. So if you are not having any OBD-I codes (have you checked for a bad O2 sensor code???) I would replace the TPS and O2 sensor if they are not already new.