The 1999 Isuzu Oasis is available as a 4-door, 7-seat passenger van. Starting at $23,680, the 1999 Isuzu Oasis S is powered by a 2.3L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 26-mpg on the highway. The top of the line 1999IsuzuOasisLS , priced at $ 25,600 , is powered by a 2.3L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 26-mpg on the highway.