Nissan and General Motors both posted double digit sales gains for September compared to a year ago. But Volkswagen sales remained flat. Nissan operates a final assembly plant in Smyrna and an engine factory in Decherd. General motors builds a sport utility model in Maury County. The companies say sales were spurred by consumers grabbing pick-up trucks and SUV’s. VW brand sales were up by about a half point over 2014. The company is reeling from backlash over revelations that it intentionally used a computer system to falsify exhaust emissions results for a diesel engine. The company has been ordered to recall 500,000 vehicles sold in the US the company makes its Passat sedan in Chattanooga.