"Out of the blue" means the same thing as "suddenly." Stick shift is a type of car, where you use a stick to manually drive the car, along with automatic car, where you just switch from park to neutral to drive, etc.
Out of the blue = 意想不到
Stick shift = [操縱變速桿(換擋的方法)] 手動換檔
(Stick shift car = 手動換檔車)