My understanding of the leak down pressure is this; there is a check valve in
the after section of your fuel pump. If your pressure leaks down, it is
telling you that the check valve is faulty OR you have a fuel leak somewhere
between the fuel pump and your gauge. I have wondered what the importance of
the check valve is - but if the
white-lab-coat-sporting VW engineers wanted it that way - theres probably a
logical reason. Bentley gives a series of checks to do to isolate leak
problems.

Brian Doss
'88 Weekender, Queequeg