Dont know much about diesels yet, but years ago Audi had problems with their computers reacting to people taking the car out of park and putting it into a drive gear. The computer would recognize the idle coming down from shifting into gear and would rev up the motor to maintain idle speed, thus launching cars out of driveways, etc. I think someone even got ran over. As you approached the corner and let off the go pedal, the engine may have gone below idle speed and the computer increased fuel. It's just a theory. My 5 speed will help me slow down till at or below idle then the idle actually makes it accelerate, was differerent to get used to at first.