I'm new to the community and have been scanning for a fix to my problem. I believe I've seen others with a similar issue, but I don't know if they've been solved.
Here we go...one day, when it was close to -20 degrees F after work and I started my Passat (1.8 T), it wouldn't start. I turned it three times with no go...by the fourth time, it started and then had the engine light on. Without noticing right away, I drove home and parked it in the garage as normal. The next day I noticed the weird fluctuating in the RPMs. I live in town, so there is a lot of 30 to 40 MPH zones, which I tend to use the cruise control for. This is when the vehicle jerks back and forth as the RPMs go up and down.
Overall, the car seems to be running fine in Park (idles what I would call normal) and after I get to highway speeds, 50 - 60 MPH, there is no more jerking.
Any help would be greatly appreciated. I'm a beginner and don't have too many tools, so dealership might be in my future.