The 2004 Buick Rainier is available as a 4-door, 5-seat sport utility. Starting at $36,695, the 2004 Buick Rainier Plus 4x2 is powered by a 4.2L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 21-mpg on the highway. The top of the line 2004BuickRainierAWD , priced at $ 37,595 , is powered by a 4.2L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 15-mpg in the city and 21-mpg on the highway.