I had 1985 Mercury Lynx diesel 4 in the early 90's that got me 60 mpg on the highway, also in the early 90's a 1985 Cadillac Sedan DeVille with the 4.3 L diesel that got 40 mpg highway. I currently own a 2001 Accent 3 door and get 30 mpg (winter beater), and ... Login to read more.