My A3 hates falling snow. It has had this issue since new. We lived in a climate with very little snow for a while, so it hasn't happened in a long time, but now I've moved, there is snow, and the issue is back. It generally happens 2-3 times in the span of a 20 minute drive, but can happen more or less.
Snow has to be falling. Snow on the ground causes no issues.
Engine at lower speeds - could just be that's where it is most of the time, but it seems more violent the lower the speed.
Bad vibration - rough shaking, extremely noticeable, sort of like that point right before the car stalls
Fluctuating revs - ECU cannot hold the engine at a set RPM on it's own, it bounces up and down over a 400 RPM range, will respond to pedal inputs but is sluggish to do so and continues to shake
Flashing CEL - first time that has occurred was today, I believe it indicates misfires, but not sure
Any help is appreciated. I know the TSI A3's have a snow/air filter available(https://www.ecstuning.com/b-mann-par...k0129620e~man/), but there seems to be no similar part for FSI models. I believe it is a misfire, but find it hard to understand why falling snow is the only cause, heavy rains have never been an issue, and I drive in those all the time.