Hoping I might be able to gain some insight in this forum as well with the issues I've been having.. Original Thread In Jetta Forum
After being at the dealer for nearly two weeks while they figured out the extended warranty coverage, they eventually diagnosed that the cam chain had skipped one tooth. They ordered the parts in (which was a minor debacle in and of itself), and replaced the chain, one coil pack, and all spark plugs. All told, I'm on the hook for my deductable, the spark plugs/labour, and about an hour of labour while they investigated a possible rodent issue, which they determined was minor and wouldn't cause any issues. They did note that there was carbon buildup that would need to be dealt with sooner rather than later, and that would still be causing the uneven idle on cold starts, but I shouldn't see any further stalling, as that was due to the cam chain. I got the car on Friday evening, and aside from the cold start idle issue, it was much improved.
I drove around all day on Saturday, and it was fine. Later in the day when I went to pick up my wife, I pulled out to pass a slower car, and there was a distinct shuddering under acceleration, which I've not encountered before, and primarily in third gear and higher. This occurred a couple of more times under light acceleration. I pulled over and plugged in my code reader, and this time it pulled a P0304 (misfire on cylinder 4), and eventually a check engine light came on. From what I've read, this seems like it's likely due to a bad spark plug (possible, given that they were just changed), bad injector coil, or a blocked fuel injector, which may be related to the carbon issue. Any thoughts as to other possible causes?
Whatever the root cause may be, it's going back to the dealer first thing on Monday.