Vacuum Problem

[The Doktor]

2009 2.5L Rabbit

Here's my problem: I got a CEL about 3000 miles ago. It was intermittent. It would come and go. Sometimes it would stay off for weeks, other times it would come on and off 2 or 3 times in a day. The code it pulled (just on a generic obd-II tool) was p0106. It indicated a MAP sensor failure or a general vacuum/barometric pressure issue. It ran fine and I only noticed a minor change in fuel economy, and didn't have the time to do any work on it.

I replaced the MAP sensor and that took care of the CEL and got me past the Emissions/Inspection (PA has both requirements) so I didn't really care.

It's only been about 500-1000 miles later and the CEL came back on. The code pulled the same. Obviously the MAP sensor didn't crap out after only 1k miles, so it's likely a vacuum leak. And there was no signs of a poor electrical connection. No noticable nicks or anything on the wiring or oxidized grounds.

Problem is, I haven't really had much luck on looking into the vacuum hoses and how they're routed. I'm going to just do a quick DIY check with some throttle body cleaner to see if I can isolate the leak, but I'm not exactly sure which of the lines are vacuum lines.

I guess I could just start hitting them all, but I felt like it would be more prudent to see if anyone has a picture or diagram of which lines are the vacuum lines and which are not.

Would anyone happen to have anything like that? Or a detailed explanation of exactly which lines they are?

I'm somewhat of a novice to intake work but do all of the basic maintenance work (oil, brakes, tuneup, etc) so sorry for the newb question. Thanks in advance for any help you can offer.

Oh... and just to answer the inevitable question... the whole thing is still stock.

 

[The Doktor]

Ok... so now the problem has gotten a little worse.

It went out on Tuesday afternoon, but this evening, it came back on again.

It was still running fine while I was driving but at some point, it almost went into Limp Mode. But not the normal limp mode where it pretty much stops you from accelerating at 20 mph or whatever. It would stop revving at 3000 rpm. I parked it and turned it off, letting it cool down for about 10 minutes before starting it up again. This time the light was still on, but the rev limiting was gone.

Has this happened to anyone else?

Any assistance at all would be greatly helpful, since I'm at a little bit of a loss for what is going on here. My mechanic told me he had seen something similar but that it was fixed by replacing the whole intake manifold, MAP sensor & vacuum lines.

Anyone at all have any other suggestions? Could it just be a vacuum line? I'm still failing to also get any help on locating exactly which of the lines ARE vacuum lines.