Technical Bulletin (Fuel Additive to Help Prevent Sporadic Misfire Faults):
Fuel quality impacts the operating performance, efficiency and service life of the engine. The use of poor quality fuels may result in deposit build up on the fuel injectors and intake valves. This may result in a rough running condition, sporadic misfires, or cold start misfire faults storing in the ECM fault memory.
A Volkswagen approved fuel additive is available to help remove and prevent deposits on fuel injectors and intake valves.
This document discusses the "Fault Codes" necessary to diagnosis, and potential remedy of the issue. The fault codes for checking warranty coverage for servicing the vehicle are also available.