MMO is the ticket here.
I soaked my cylinders in it for 4 days straight, ran the car for about 10-20 miles and gained compression it did a great job.
in a 240D with 219K miles on it,
my compression (cold) at first was
400
360
380
390

after soaking for 4 days my cold compression was:
395
390
385
385
definitely an improvement in cylinder 2 wouldn't you say?

before you do anything do that.

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'82 240D 224K miles manual transmission
mods: wooden 4by4 bumper, EGR delete and older EX manifold without EGR port, glass pack muffler (cheapest replacement muffler), rebuilt bosch injectors with Monark nozzles

working on: aux electric fuel pump, coolant/fuel heat exchanger/filter head, afterglow, low oil pressure buzzer/LED