The Cutlass was once among the best-selling U.S. cars. In the late 1970s, GM decided to take advantage of its popularity and develop a diesel version. The 4.2-liter Olds diesel engine was sold only in the 1979 Cutlass. Unfortunately, GM hadn't yet mastered diesel technology. "GM was trying to market a technology that wasn't ready for prime time," Oldham says. "The cars never really ran properly. They were underpowered. They blew up. They broke. It was a warranty disaster for GM." The engine "reached 90 horsepower before shattering into shrapnel," Edmunds.com wrote. The failure of the Cutlass diesel "turned Americans off to diesel," Oldham says. "It is one of the reasons why diesel is still a bad word in this country."