Reving out of control possible causes:

1. Bad IP internals or external (linkage stuck?)

2. Engine oil level too high fuel sucked in through the rings.

3. Too much blowby getting into intake.

Not sure if a torn IP diaphragm dumps fuel into the crankcase. If so, check oil level and if high or smells like diesel you found the problem.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked