Preliminary estimates for auto sales in June call for a modest gain for June of perhaps 1% or so. Maybe not for GM. TrueCar.com analysts think the company’s sales will be off by as much as 3%. But the company has trimmed back low-profit fleet business, and cut its average incentive by 11% per vehicle last month. Larry Dominique, executive VP at TrueCar, says it's actually good that CEO Mary Barra isn’t just pushing volume with incentives.