The Chevy Vega -- Clean Lines, but beneath the skin....
Later my father purchased a 1972 Mailbu that was by all accounts a great car, and then as he approached retirement, he bought a 1979 Malibu Classic. It was that car that turned me against GM, because it had a THM-200 transmission in it that was far too small to be coupled to a small block V-8. Consequently, the car kept on blowing tansmissions, one after another, and GM never made it right it with my father. They kept ducking the problem, and thus my father, who had purchased this car to travel during retirement, was greatly disappointed. I owned it for a while after my father died, and ultimately solved the problem on my own by replacing the the THM-200 with a more durable and appropriate tranny. And it had other issues, including weak springs and valve guides that wore out way too soon, given the care it received.
For what it is worth, and given my bias, here is the list of the 5 worst GM cars, compiled with the help of Sean Falkowski and Rebecca Blust.
1981 Caddy -- or is it a Citation in disguise?
3. The J Body Cadillac Cimmaron -- This early 1980s model was a response to the 1979 oil shock and subsequent recession. GM decision-makers took a brand that was the standard of the industry and degraded it to such depths that Cadillac only recovered from this insult during the past 5 years. Old ladies drove this car in the 1980s, thinking it was their final luxury car. As it turned out, their last ride was in a Cadillac hearse, which remained of high quality only because undertakers would not settle for vehicles anything less than the best.
4. The HT-4100 Cadillac of the early 1980s. Another failure for Cadillac was due to the hasty introduction of an engine that could be run on either 4, 6, or 8 cylinders depending on the need to do so. It deactivated cylinders via solenoids, but overall was an engine that lacked power, and torque. The engine was thrashed in just keeping up with traffic, and consequently rod bearings failed and its coolant leaked.