First of all, thank you for taking a sec to stop and read the thread. Any and all input will be greatly appreciated. In the back ground story, I have a 2001 1.8T that I gave to my g/f to drive as her daily. The tags expire at end of October, so I told her I will need to take it for a couple days to get inspection and emissions work done. She decided to wait till now to let me know it had a CEL on. I took it to Autozone to get a quick scan and ended up with 4 total codes.. P0411, P0300, P0301, P0171. Mind you I deal with investment banking as a job but enjoy tinkering with cars and have for years, though I am no mechanic. Anyways, I did my basic online research and at this point am narrowing my field to being a vacuum issue. I pulled out air box and checked all vacuum lines I can see. Shy of getting a smoke test done, I don't see any issues in lines. My next thought was to test EGR(Kombi Valve) to see if the plunger is stuck as well as replace the PCV. I just wanted to see before I dump cash I don't really have right now, into this issue, if I am going in the right direction or if anyone has ever seen all of these codes pull for a diff reason? Any advise?