Q: Car jerks hard before stop and when accelerating from stop position. Only when the car is warmed up.

The source of the fault first has to be distinguished as "transmission versus engine". Of course, there can be issues in both components, too. If this is transmission related though, I see at least three Volkswagen technical service bulletins (TSB’s) that describe repairs for the jerking malfunction that you are describing. Consequently, the car should be test driven by a mechanic and he or she would compare the results against the advice in those specific TSB’s. If the issue is the engine, this would ultimately be handled in a "loss of power" diagnostic. What I suggest that you do is simply go that route, request a loss of power diagnostic and the responding certified mechanic will deal with all the possibilities and will certainly determine the applicability of those TSB’s. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.