The below is tank part numbers are the size of GAL= tank no matter what your build sheet says. I have a 99TJ and thought it was a 19 Gal but the part number on tank and cross reference to below chart shows it is a 15.Gal. Now I know why 11.5 gals is the max I can get in tank at fill up.
EP0=All 2.5L Gas Engines
ER0= All 4.0L Gas Engines
52018 687AB 1 EP0, 15 Gallon
52018 768AB 1 EP0, 19 Gallon, 1998 TJ, 1999 TJ
52018 768AC 1 EP0, 19 Gallon, 1997 TJ