You have a mouse nest or other obstruction in the plastic hose leading to the air filter housing.

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1982 240D auto
1978 300CD auto
1985 300D auto
1983 300TD auto
1984 Porsche 944 5 speed
1973 Opel GT 1900 4 speed
1967 Chevy C30 350 Sm420
1973 Mustang Grande Convertible 302 C4
1981 VW Pickup 1.6D Turbo 5 speed
1983 Rabbit 1.6D Factory Turbo 5 speed
Plus parts vehicles...

there was no kink in the breather hose, it was actually cracked in half. it was taped together with electrical tape but was not blocked. i never had this issue again with this engine, but it developed a bad oil leak and has since been replaced with a $150 junkyard engine, about 7 months ago. 10,000 miles later so far so good!

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1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo