There is a TSB on the 2005 Kia Sportage that sounds like your problem. Check with KIA at the toll free number below or the dealer as they may repair this free of charge.
2005 KIA SPORTAGE
Manufactured between: 10/28/2004 and 03/26/2005
Defect: on certain sport utility vehicles, fuel may leak from the o-ring into the internal vapor chamber located in the fuel tank at full tank conditions.
Consequence: the engine may stall when coming to a stop. it will be hard to fill the gas tank and external fuel may leak from the evaporative air filter inlet. fuel leakage, in the presence of an ignition source, could result in a fire.
Action: dealers will inspect and replace the fuel tank and replace the charcoal canister free of charge. the recall began on may 31, 2005. owners may contact kia at 1-800-333-4542.
Recall Date: 05/03/2005