1995 740il skip on cylinder 4, not just in idle though!

[obraun250r]

ok! here we go!
i very well know about the good old early production m60/m62 compression problems. they will cause a rough idle but once you accelerate the engine it will run smoothly on all 8 cylinders.

here is my problem:

i have this 95 m62 engine which has not been updated enginewise! it idles rough but will also continue to carry the skip into higher rpms. i know which cylinder it is. the coil receives an impulse and will fire. the injector pulses too. when i pull the plug, it is pretty wet though. i have a retriever computer diagnostic system. it will not show me any live data values of the isolated cylinders, like injection timing or firing (as it would on a m50 or m 40). so how do i know if the dme gives fire and fuel impulse at the right time, duration and strength?

i wanted to swap the dme module with another car's which was made in the same month and year as the one i'm working on only to be remembered that from 01/95 all dmes are "married" to the ews, so you cannot swap them out between cars like on an e32, e.g. anymore. any suggestions what to do, to find out what the problem is without throwing parts on it?

thanks, any suggestion is appreciated