WASHINGTON (Reuters) -U.S. factory production unexpectedly increased in August amid a rebound in the output of motor vehicles and some nondurable goods, though tariffs continued to cast a shadow over the manufacturing sector. Manufacturing output rose 0.2% last month after a downwardly revised 0.1% fall in July, the Federal Reserve said on Tuesday. Economists polled by Reuters had forecast production for the sector, which accounts for 10.2% of the economy, would slip 0.2% following a previously reported u ...