But Dad said, "She runs good."

The Oldsmobile Delta 88, featured in "This Never Happened to Superman", is one of Forbes' Worst Cars of All Time:

GM had two famously bad engines in the early 1980s: one that could operate on four, six or eight cylinders, and an Oldsmobile diesel. While the "variable displacement" engine was a pioneering idea that is just coming back on cars, the worst it usually got was that owners would have to clip undercarriage wires to get away from malfunctioning four- and six-cylinder modes. Oldsmobile's 5.7-liter diesel, which appeared from 1979 to 1984 on the Delta 88, was a bigger problem--a converted gasoline engine that was just a disaster. It would "smoke," demonstrating "rough idle" and "reduced performance," according to service bulletins.