I would guess that it might be a plugged PCV system. The ones on the NA cars are quite a bit more complex and subject to damage and blockage. More so than the turbo version.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250