Yours is not stock. The whole thing is a modification.

 

Yup.

I'm getting around 250-270 per tank. 4.6 stroker, 35's, 4.88's for gears.

 

I've driven from DC to RI on one tank. That's 375 miles. With smoother tires I might be able to crack 400.

 

I have a 97 XJ with 3" lift and 31" km2's. I drove it this weekend home for easter. Its all highway running 75 3/4's of the drive. I was rather impressed with what i got since i normally drive all city miles and get terrible mileage.
I filled up after 160 miles and got 17.8 mpg. I still had about an 1/8 of a tank above half. I was going to wait and drive home and try going until it was on empty but had about 20 mph wind to drive into the whole way so figured it would throw it way off.

 

I have the factory option 28 gal tank and no problem to get over 400 miles.

If you can put over 20+ gallons in your tank- you might have this option. Check the build sheet

 

I drive five city miles 15 mins to work everyday and get 200 miles to the tank on 87 octane (first tank of gas). I let it empty till the light came on and filled up with Slick 50 high mileage fuel treatment and some 93 octane.

 

What's the part number for this phantom 28 gallon tank?

If you're talking about the "extra 8 gallons fuel" option on some build sheets, that's not a larger tank. They just put more fuel in the standard sized tank at the factory than the 2 or 3 gallons they usually include for moving the vehicles around.

 

Just commuting from work, school, and average run arounds anywhere between 200 and 230 miles. Winter between 180-200. My milage sucks

 

You could be correct- but I put 24 gallons of gas in the tank today- so that would be weird- maybe a vent mod was done.

 

6.5 inch long arm lift, 35s, 3.55 gears and I'm getting 250-270 a tank

 

Or you could have an aftermarket tank. There are at least three companies that have made aftermarket extended range tanks for the XJ.

 

Approximately 100 fun packed miles in the deep and soft sand.

 

everyone that's says that they fill up when fuel light comes on need to see how many gallons of fuel go in the fuel tank when they fill up. On mine the light will come on when I still have 4 gallons of fuel left in the tank which if you don't take into account will mess up your miles per gallon average

 

For me it's the 15 mph at 2000 rpm that eats gas.

 

I get on avg. about 16mpg all city driving. Stock 98 4.0l 4x4