black2000xj

yes i get about 16-18 combined city/highway

i just changed all the fluids, replaced both o2 sensors, new ngk plugs
cleaned throttle body, new air filter

im stuck in between 16-18, but that really isnt bad with 31" tires

of course i let it shift at 2100 rpm everytime

oh and i reset the ecu, between that and new plugs, those things made it feel alot stronger and more efficient

abbeysway

I just drove 5000 hwy miles averaging 21mpg with Thule carrier & Yakima racks on top. At least 500 was in 4wd. I previously replaced ALL sensors & ejectors to 4 port Bosch over the past 12 months.. All Amsoil fluids, but doubt that made any difference. Made the same trip in 2013 & got 17, without the carrier on top. Hwy mileage has been averaging 23, plus or minus without the racks, since the changes. I have a 2000 Cherokee Classic 4.0 liter engine with auto trans.

Pretty pleased with the results.

George

BlueRidgeMark

No, it's not a Jeep thing. It's a problem thing. I get 17-19 consistently, combined mileage, on a box stock rig. My 94 and my 97, same thing. That's normal.

If you aren't getting that, something is wrong.



Higher octane gas isn't going to get you anything but money wasted.

cbs_24

I'm getting exactly 16 mpg according to my gas tracker app I've been using for my last ten fill ups.

Ralph77

When I first bought my '00 I was doing a little worse then TheNovaman. Decide to see what I could do about. Swapped all 4 of my O2 sensors. Justified it by telling myself that they probably had 150K on them and needed to go. Upgraded to 4 holes injectors. Swapped front and rear diff fluid for a synthetic. New Cooper Discovery HT's in a 225 75 15. Jeep is stock. Doing 16 maybe as much as 17 MPG around town. On the longer highway runs thinking I might be doing as much as 22 MPG. This is with taking it easy on the skinny pedal.

jpz

Those numbers seem about right. Pretty much match my numbers for a bone stock Cherokee.

Waynerd

The other day a coworker said" I smell gas". I said "that's because it's coming out my tail pipe. Lol. Upstream o2 unplugged at the moment, let u know the mileage once I replace it. Right now it's horrible.

BlueRidgeMark

Not only is your gas mileage horrible, it's diluting your oil. Make sure you change the oil soon!

Been there, done that.

WyoCherokee

With whats in my Sig, and a roof rack with tire on top and 32" aggressive all terrains, i get 14-15.5 highway at 70. Tires play a big deal. i get better mileage with my ATs than i did with my MT's

t.mcginley.jr

My 2000 XJ 4.0 auto, 202k miles (~150k on the engine) is stock minus an aftermarket header and gets 16-17 mpg with 30/70 city/highway. Sitting in traffic doesn't help my numbers though, I've yet to see what it can do strictly with highway miles.

Also i do ~80 mph on the highway so I'm sure that brings my avg. down some.

BlueRidgeMark

"Some", he says!


Take a minute next time you are out on the highway and see how much throttle it takes to maintain 80 vs. 70 vs. 60. You might shock yourself.

These flying bricks of ours just aren't built for rolling down the highway at high speed.

t.mcginley.jr

Oh I'm very aware haha, all of my gas on the highway goes towards overcoming wind resistance. Also I'd like to revise my previous statement to ~80-85 on the highway

The only things less aerodynamic than our XJ's are Hummers, buses, old Bronco's... it's pretty bad

JeepCherokeeSport00

I was managing maybe 8-12 mpg city/hwy when I first got my XJ.

3/4 tires were at 20psi. I topped all 4 up to 35psi. Swapped the spark plugs to some APP985's and put in some 784 injectors. Reset ECU. Some minor fluid maintenance. Everything else is stock.

Now according to my OBDII I can get at least 25mpg avg. hwy. Not sure how accurate that is, but I was pretty light on the throttle going at least 65-70.

s346k

stock with homemade air intake and 703 injectors mine averaged 21 mpg 70% city. I managed 23.9 in August with the ac blowing on a mostly highway trip, cruise @ 76. I lifted it ~2.5" and put 235/75s on it and averaged 19 mpg 50/50 city highway. I averaged 17 mpg last tank with over 4 hours of idle time. there's no reason it shouldn't get at least 18-20 mpg mixed if it's stock on 225 or smaller tires. my jeep is meticulously maintained.

Gunmetal Pearl XJ

I'm averaging 15 with 87 Oct Holiday gas. What Octane are you guys filling up with?