Hi guys, I have the 2005 A4 1.9tdi about 137,000 miles. Its gets serviced and maintained well. Whilst driving normal or at speed the car now and then i feel a judder or a misfire. Im assuming it could be bad diesel? Fuel filter was replaced around 5000 to 10000 mile ago so I dont think it could be that. Im going to put some treatment in the tank to clean injectors and run that tank down to put some shell vpower in and see how that goes. However if this doesnt sort the issue does anyone know what could be the problem???
I also been told to look out for flywheel symptoms. What are these symptoms? Thanks.

Lee