1998 Daewoo Leganza with the oil light staying on although there is plenty of oil in the engine?

1998 Daewoo Leganza with the oil light staying on although there is plenty of oil in the engine?
Probably you need to replace the oil pressure sending unit. It is located on the engine down close to the oil pan. If the sending unit is leaking oil then replace it by all means. Doubtful that the oil pump is defective.