Just had an idea today... To diagnose the supposedly blocked vacuum line, try finding a piece of piano wire and snake it down the line from the top end near the check valve. This should reveal any obstructions and may clear them out if used in combination with a little compressed air shot in from the WG transducer side.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250