Coil packs (ignition coils) are susceptible to failure. This has been widely documented by VW owners and there is now a recall campaign (2011). In my opinion, VW severely damaged their reputation by not issuing the recall on these coil packs sooner. Many, many VW owners were stuck with the bill on replacing the flawed coil packs. I ended up replacing 3 of the 4 coil packs on my own dime (purchased and installed myself) a few years ago. They recently just replaced all of the coil packs for me under the recall, after I had already spent ~$200 replacing them before the recall.