Now do you notice the air flow slowing down when at idle or speeding up when the engine speeds up? Might be a weak charging system allowing the heater blower to change speed.
Does your Passat have the electronic climate controlled heating system or just some dials to control the heat? The electronic system might have vacuum devices, but the mechanical dials should not.
Here are two Passat specific yahoo groups you can join. snipped-for-privacy@yahoogroups.com snipped-for-privacy@yahoogroups.com
Even non-electronic systems may use vacuum controlled vents. It could be a vacuum problem.
where is cylinder # 6, is it the left (drivers side) towards the radiator or firewall
I think you are right! If the a/c is set on Recycle then flaps will close off the external air inlet. I can't think of any other vacuum vents though. Which other vents on a 2000 Passat would be vacuum controlled with the mechanical controls that would cause the OP's problem? That is if it is even an "air flow" issue! ;-)
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