The 1999 Cadillac DeVille is available as a 4-door, 5-seat sedan. Starting at $38,830, the 1999 Cadillac DeVille Base is powered by a 4.6L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 17-mpg in the city and 26-mpg on the highway. The top of the line 1999CadillacDeVilleConcours , priced at $ 43,430 , is powered by a 4.6L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 17-mpg in the city and 26-mpg on the highway.