Gas tank wont fill up all the way.

[Johnnie Walker]

There is a write-up for a mod, either here or over at cherokeeforum where you can adjust or modify the in-tank vent tube to increase your tank capacity,

 

[PhotographerMike]

The "20 gal." tank does hold 20 gallons, but the low fuel light comes on with 3 1/2 gallons left because with a Jeep you might not be close to a gas station if you're using it right. A 13 gal. tank is the same size as a 20, the vent tube just goes deeper into the tank so the factory could offer an optional 20 gallon tank without having to actually have two tanks. I have heard that the vent can be easily shortened for full capacity.

I did the "get more in your tank" modification on both of our Cherokees and can now fill them up with 22+ gallons if they are truly empty and 20 gallons when the light has been on for a couple of days around town.

 

[ZJeepX]

The "20 gal." tank does hold 20 gallons, but the low fuel light comes on with 3 1/2 gallons left because with a Jeep you might not be close to a gas station if you're using it right. A 13 gal. tank is the same size as a 20, the vent tube just goes deeper into the tank so the factory could offer an optional 20 gallon tank without having to actually have two tanks. I have heard that the vent can be easily shortened for full capacity.

I did the "get more in your tank" modification on both of our Cherokees and can now fill them up with 22+ gallons if they are truly empty and 20 gallons when the light has been on for a couple of days around town.

thats pretty interesting a 13 gallon really is a 20