The year 1984 was a more year of waiting rather than major changes for Cadillac Deville. The reason behind is that, during this year Cadillac engines were fuel injected. In this year, the 249 cubic inches engine gained new exhaust system and catalytic converter, and revised calibration settings. The purpose of these is to meet high-altitude emissions standards of the vehicle. Diesel engine identification plaques were on the left rear of the decklid.

 

1984 Cadilllac Deville has a modified optional theft-deterrent system that could detect any object on the driver's seat that weighed 40 pounds and more, when placed on the driver's seat. There are new features on DeVille, the Fleetwood Brougham and limos included a goldtone horizontally-winged Cadillac crest ornament on front parking and turn signal lenses, the new car-colored bodyside moldings, the new goldtone vertically-winged Cadillac crest and goldtone accents on taillamp lenses, and the new standard electronic level control. This is a luxurious and a very fun to drive car, with a magnificent comfort and powerful.