In modern cars with a great deal of electronics low battery voltage can cause all sorts of problems. The magic voltage seems to be around 10.5 vdc to 11.0 vdc, at that voltage computers, ignition, fuel pumps, and etc can become a little nuts, and then you throw in even lower voltage at idle or very low engine speeds and your car can do a lot of strange and wonderful things.

2009 Sorento LX, 4x4, V6, Auto, Red