Leak from egr or vacuum? How to diagnose hissing noise at certain RPM. Replacing inje

My 00 VW TDI: diesel filter, engine oil, trans fluid and filters for both replaced. New air filter, sea foam ran through diesel for 120 miles. Code for MAF, bought new one. Recently drove, on way back... a hissing noise like leak from exhaust or vacuum through egr or vacuum lines. Just replaced main vacuum line from turbo. Little oil on turbo, concern on leak. Exhaust manifold replacement for performance?

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Well, your EGR and that pipe look great! If your intake manifold is as clean,
you don't need to replace it.
Sometimes those accordion pipes develop hard-to-see hairline cracks. Check that.
Also, VCDS will give you better results...by far.
http://wiki.ross-tech.com/wiki/index.php/16485/P0101/000257
Searching your code on ross-tech gives a lot of help too. Check "Possible Solutions".
Just inspecting/replacing all the vacuum tubes is warranted at that age anyway.
And here's a nice table of the systems grounds:
https://web.mit.edu/dennis/www/vw/grounds.html