I have a 2003 VW Jetta GLS 5 sp. Manual with the 2.0 Naturally aspirated 4 cyl engine. The car has approximately 147,000 miles. My MIL light has been on for some time now. I recently got my local mechanic to run diagnostics on it and he reported two error codes (411 and 420). To my understanding, 420 is due to the imminent failure of a catalytic converter, an issue which I have addressed by replacing Plugs, wires, distributor, and cat.
My real question is, I would like to know if a mysterious Vacuuming sound that comes from my car whenever I start it cold in the morning and persists for about 25 seconds, and then comes on and off intermittently, is related to the 411 code. My local mechanic told me that there is some kind of exhaust recirculation motor that may be going bad.
Please help. I love my VW and want to keep it running properly rather than give it up, so long as there is no serious problem that is impractical to fix.