The 2010 Cadillac DeVille is known as the DTS in most parts of the world, and like most large luxury cars the '10 DTS is relatively heavy. Tipping the scales at approximately 4,009 pounds (depending on configuration and options), it is not surprising to see that the newest flagship luxury sedan from Cadillac struggles to garner an official EPA rating of 15 miles per gallon in the city driving and a meager 23 miles per gallon on the open highway.
 While weight is certainly an issue in a car this size, the aging 4.6L Northstar engine and four speed automatic transmission are showing their age. With numerous competitors from both home and abroad offing similar power with only six cylinders and far less displacement, not to mention the use of regular unleaded fuel versus Cadillac's reliance on premium high-octane fuel, it would seem that the weak link in this luxury sedan is under the hood. It is also worth noting that GM's Northstar system is fairly heavy when compared to rivals, and the company plans on phasing the aging platform out in the near future in an attempt to remain relevant in a highly competitive market.
 The fuel efficiency in the 2010 Cadillac Deville is further hampered by poor aerodynamics. The new Caddy sure looks the part of the stalwart American luxury sedan, but that old-school appearance costs points when it comes to drag. Unfortunately for environmentalists who would love to drive a Cadillac, image is certainly an important aspect of the brand and thus it is probably fair to say that the aerodynamics are unlikely to change radically in the near future.

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