Hello, I'm Jason. I will do my best to answer your question quickly and accurately using the information you have provided.
Good Evening. What else can I tell you?
Well, this will be an answer based on my experience with these cars, since right now, we don't know the exact code that the engine controller has stored
From your description, the most likely culprit is the crankshaft position sensor....
and I can certainly upload a picture of this component if that would help
I'm also one who would rather have firm data showing that this is the problem rather than "shotgunning" parts at the problem
But also understand that this can be related to an interruption in fuel delivery as well
Still with me?
So, to accurately pinpoint the problem, a scan of the engine control module would be best, XXXXX XXXXX you find the following codes: P0321, P0322, P0335, P0336 or P0337, then you definitely need to change the crankshaft position sensor
Would those be considered ignition codes? Is this a DIY type of replacement? Is the part expensive??
Yes, the crank sensor would directly affect spark output. Often as this sensor starts to go bad, it's very sensitive to heat changes, and as the engine warms up, the sensor begins to fail....
First, here is a picture of the sensor itself
Now, I'll show you exactly where it lives. The picture I'm posting is the same sensor on a 1.8L turbo engine, and the difference is that the 2.0L sensor wire is much longer, and the harness connector is accessed from up above the engine rather than where it's shown in this picture
And it is held onto the engine block by a 5mm Allen bolt
So far, so good?
Yes, I'm with you.
Excellent. But again, please understand that I'm basing this off of my own extensive experience with these cars, since we don't have any hard data yet
Having trouble with links to view full size images, but I have a Haynes Manual or can google photos. If this turns out to be the issue, is there any need to reset anything once the sensor is replaced in order to get the check engine light to turn off?
The light is not likely to turn off by itself, but any generic OBDII scan tool will do this. I'm also going to upload the picture a different way, so that you won't have to spend the time searching.....in the meantime, I'll give you a link to a great VW parts source for this sensor: http://www.ecstuning.com/Volkswagen-Jetta_IV--2.0/Search/Position/ES1874/
How is that?
Much better. Is that looking down from top or looking up from below? Is it under the oil filter??
That's looking up toward the oil filter. But again, the wire is quite a bit longer on the 2.0 (I don't know why), so the grey harness connector needs to be dealt with from up top
OK great! I'll need to get someone to put a diagnostic tester on it, and hopefully it throws out one of the codes you mentioned above.
Thanks so much for your time and help.