Purchased a 2011 Ford Taurus Limited with only 55k miles. Car drove great during the test drive, without any issues. About a week into owning the vehicle, we noticed that the transmission will stall at a stop light, or stop sign. It doesn't happen very often, but it's quite annoying when it does, especially with the car having so little miles. Now the car has over 100k and the problem is still there but only happens from time to time.

Car will shift out of drive automatically and then shift back in while driving. Cannot make car do it for the dealer and happens sporadically. Dealer just says sorry, can't fix what we don't know is wrong.