* 19-gallon tank: This was the standard size for most 1998 Wranglers.
* 20-gallon tank: Some models, particularly those with specific options or packages, might have had a 20-gallon tank.
To know for certain the size of the tank in *your* specific 1998 Jeep Wrangler, check the sticker inside the driver's side doorjamb or your owner's manual.