My wife’s 2011 Volkswagen Jetta (2.0 I believe) is misfiring again. We took it to the dealership about 6 months ago and they said that the ignition coil had gone bad. They replace the ignition coil and said that the plugs needed changing as well. I went to Auto Zone and got some decent plugs and changed them myself at home without much problem. It seemed to help the problem (although it didn’t seem to completely fix it) for a while, but it just recently went back to misfiring. The current symptom is that it seems to misfire when the car is warming up, but misfires less when the car is warm.
The dealership says that the plugs that we got were not recommended by the dealer (they recommended Bosch) and that they need to be replaced. I think this is BS and it is not going to fix the problem. Could the ignition wires be the problem? Any other suggestions?
Thanks for your help,