I keep getting a CEL and it shows insufficient SAP flow on banks 1 and 2. I've replaced all the vacuum hoses and this helped a bit but the CEL light will come back on after a few hundred miles after I reset the light with the same code.

When start first starting the car when its cold, the engine sounds like a jet engine (loud roaring) running for about 30 seconds before the noise dies down. I also get a strong engine smell coming into the interior of the car when sitting at idle at a stop light all the time. I found the source of the smell is is coming from the vacuum regulator/pump area near the where it attaches to the front part of the intake manifold.

Can anyone give me some help here? Thanks in advance

 

Most likely the pump itself is failing

 

I have the same problem on my 2001 A6 2.7T. Did you find a solution to the problem? Thank you.