12: Chevrolet Camaro Iron Duke
The Iron Duke was a massive flop for GM, so much so that it almost tarnished the entire product line. The Iron Duke was the lethargic four-cylinder engine that GM was selling at the time. The modern four-cylinder motors that we have today are nothing like the awful engines coming out in the 1980s (via Auto Blog).
The Iron Duke is one of the most despised models ever released by GM. The performance of the car was not what Camaro loyalists had hoped for. Even though GM was working on trying to build a more fuel-efficient car in a pinch, the result just didn’t make sense. The Camaro was not meant to be an eco-friendly ride.