DETROIT — U.S. sales of new vehicles are expected to have struggled during the third quarter amid economic and political uncertainties, as well as elevated interest rates and prices, according to industry forecasters.Sales are expected to fall roughly 2% during the third quarter compared with the same time in 2023, to about 3.9 million vehicles sold, according to Cox Automotive and Edmunds.com. That would be a roughly 5% decrease compared with the second quarter of this year.Analysts note that the Federal R ...