US factory production unexpectedly fell in March after two straight months of solid gains, weighed down by decreases in the output of motor vehicles and a range of other goods. Manufacturing output dipped 0.1% last month after an upwardly revised 0.4% increase in February, the Federal Reserve said on Thursday. Economists polled by Reuters had forecast production at factories would gain 0.1% after a previously reported 0.2% rise in February.