When I drive my car sometimes in will go into a lower gear especially if I'm sitting idling for a long time but if I turn the car off and back on again it goes away but not always.It doesn't happen all the time but when it does it's annoying.When it drops into the lower gear when I reach 90km a hour it starts to shake.I had it checked at the transmission shop and they said it's not a transmission problem but a motor problem.It may have something to do with the computer I think.