Just checked my mileage today and it came out to 15.4 mpg. Mostly freeway miles. Is there anyway to squeeze a little more out of it or is this about as good as it gets? It has the following:

3" lift
30x9.50x15 Tires
Automatic
4.0
All else stock
145k

Recent maintenence:
Tune up (cap, rotor, NGK plugs)
air and fuel filter
seafoam
all fluids changed (oil, axles, etc)
removed and cleaned throttle body
PO replaced cat and exhaust manifold

I havent done anything with the O2 sensor, I pulled it and it was really white however it isnt throwing any codes or anything. Should it be replaced as precautionary?

How much does the 30" tires throw off the actual mileage? Is it insignificant?

Anything else I can do? It seems to run pretty well, seems to idle somewhat rough sometimes, kinda shakes at stoplights.

the 30's shouldn't hurt your MPG too much. im running 31's and on the highway i can get about 18 MPG if i'm easy on the gas.

do you have a lot of extra stuff in the back? give it a lot of gas? a lot of extra weight will decrease MPG also. but with all the work you stated, thats pretty good for helping MGP.

Not much weight. Some tools (a must with a Jeep), tire chains and thats about it.

The tires are a mud terrain style.

I'm pretty easy on the gas, do about 65 on the freeway. Some of the driving was around town, but not much.

My last tank mileage was 17 mpg. mostly highway, but cold weather start-ups. Stock Cherokee, with the 4.0l and auto. Have a K&N Filter. Watch your tire pressures and keep that air filter clean. some simple tips.

hmm. not sure then. i dont think the MT's would make that much of a difference since they're only 30's. when you did your lift, did you do an sye and install a new speedo gear? you may be getting better gas mileage than you think.

Did the t-case drop and no speedo gear. Thats why I was wondering what the difference was with the 30" tires (Does 1 mile shown really equal 1.1 miles or whatever)

hey man don't feel bad with the 15.5 miles to gallon. I get about 12 all winter with mine with a 3.5 RE and 31s. Towing one snowmobile on a trailer i get about 8mpg.

LET HER BREATH ,IF YOU TAKE YOUR TIME AND SEARCH, YOU CAN PICK UP A HIGH FLOW CAT AND MUFFLER FOR UNDER A HUNDRED BUCKS.THEN THROW A BACK YARD COLD AIR INTAKE ON IT.FILTER 25.00 AT THE ZONE,3" INCH PIPE FITTINGS 10.00 BUCKS AT DEPOT.

What type of increase does a catback and high flow muffler give? I was thinking of doing 2.25 and a flowmaster.

Here is a look at my O2 sensor. Can it be cleaned or just replaced?

My 2001 XJ with 3.5" RE lift and 32s get between 15-16 mpg.

My 94 with a CAI and Cat-Back Dynomax on 33's dosnt get better than 13mpgs.... It is sad... But this week I am going to throw on a new air filter and put a shiel under it to try to stop it from geting caked in mud... or maybe a Home made snorkal... and due a full tune up.. Plugs, Wires, Cap, Fuel Filter and a Fuel injector cleaner... hopefully I can get up thre aon those Dreaded MPGs

that looks like you got antifreeze or water or bad head gasket.. shouldnt be white and no get a new one no cleaning it.. but white isnt good

I noticed a gain from my ported TB and K$N FIPK. try changing gas stations.....I picked up 1.5 MPG going over to Exxon.

if you replace those old o2 sensors you should gain some mileage but you need to change you speedo gear to know exactly how much and my 2000 with a 5.5 inch lift and 33's gets around 12 so don't feel to bad

What plug wires are you running? If you upgrade to at least a 8.5mm wire that should help some. Exhaust will def help, the inlet of the cat is 2.5.. so why not go 2.5 all the way back?