My 2006 Jetta TDI used to be driving fine and then it would stutter and drive fine again. This normally happened around 25 or 45 mph and the car would run fine before and after. Recently, the car would run fine and then stop by itself. It would turn off and you would not be able to start it again. After sitting for a while it will start. It has done this a few times. What can be causing these issues? Are they related?