Detroit — General Motors Co. CEO Dan Akerson wants the federal gas tax boosted as much as $1 a gallon to nudge consumers toward more fuel-efficient cars, and he's confident the government will soon shed its remaining 26 percent stake in the once-bankrupt automaker. "I actually think the government will be out this year — within the next 12 months, hopefully within the next six months," Akerson said in a two-hour interview with The Detroit News last week. He is grateful for the government's rescue of GM — "I have nothing but good things to say about them" — but...