DETROIT ( TheStreet) -- GM ( GM) is benefiting from an industry and product revival that has pushed its share price up 20% this year. But in the largest segment of the automobile market, GM is faltering. That's because the Chevrolet Malibu has not carried its weight in the midsize car segment, where the largest U.S. automaker has just 7% of the market, according to figures compiled by Kelley Blue Book. Market leader Toyota ( TM) Camry has 16% market share. Honda ( HMC) Accord, Nissan ( NSANY) Altima and Ford ( F) Fusion all outsell the Malibu. Now GM has pinned its hopes for the segment on the September rollout of the 2014 model. But some experts sound skeptical. Malibu's lackluster performance stands in stark contrast to GM's achievements in other segments. The late summer introduction of the new Silverado into a booming pickup truck market represents exquisite timing. Sterne Agee analyst Michael Ward wrote recently that "the changeover to the new pickup trucks at GM is the biggest transition in the industry in 2013." Last month, the new Impala, a large sedan, became the first Detroit vehicle in two decades to be named the top sedan by Consumer Reports. And the Lordstown, Ohio, Cruze plant won't shut down next week, as it had been scheduled to do, because demand is so high. In July, sales of the 2013 Malibu sales rose 1%, but for the first seven months sales are down 20% to 123,573. GM was so unhappy with the performance that in May it announced it would roll out the 2014 model this fall. GM spokesman James Cain said the 2013 version "is holding its own," with increasing month-over-month sales and improving retail sale. The 2014 version will be "more roomy, more fuel efficient and have more technology and more features, (and) it will be a big deal for Chevrolet dealers," Cain said. "We think it will do well in the marketplace." No doubt the Malibu rollout will garner attention in the auto industry. "If it's well executed, it's a domestic rival" to Ford Fusion, said Edmunds.com analyst Jessica Caldwell, noting: "The new Malibu could upset the apple cart for Ford." Kelley Blue Book analyst Karl Brauer agreed that GM "has to execute flawlessly.