My recent purchased Vue with the Honda v6 and a/t had a vibration at around 1400 rpm that was caused by the transmission. It is a very common problem with this transmission, in Vues and Hondas as well. It is caused by the
aggressive converter lock-up and requirement for frequent fluid changes. You can add friction modifiers that help temporarily but changing the fluid about every 25k miles with honda spec fluid or equivolent (I used Valvoline synthetic from Walmart as it works and is cheaper than the fluid from Honda) is the better solution.