One problem related to auxillary tank has been reported for the 1998 Kia Motor Sephia. The most recently reported issues are listed below.
Refuel spit-back. Fuel will spit out of fuel tank upon refueling the car. Fuel will usually spit out when tank is 3/4 full (avg of 6. 3 gal. ) however, will spit back at 1/2 gal. As well. Paint beneath gas fill port has been completely disolved, body damage also occurring.