One problem related to o2 sensor has been reported for the 1998 Kia Motor Sportage. The most recently reported issues are listed below.
Recall 99v325000 concerning stalling. Vehicle was experiencing an electrical problem that interfered with performance. Vehicle was recalled and repairs done, but symptoms returned. Manufacturer claimed no responsibility because consumer was not the original owner. Check engine light was on. The vehicle vibrated, smoked and was overheating. The left front tire blew out. Ignition coils cracked and were replaced. Vehicle had a blown head gasket. Front left turn signal clips broke. Oxygen sensor failed. Right front door lock fell off. Vehicle had several parts on recall before the consumer purchased it and the consumer believed those recalled parts were the source of the problem.