Injector seals were repalced about 2 months ago so I assume they are OK. I agree with you that it is a combinatin of multiple part not working optimally, with electical quirks being either the cause or the symptom -- impossible to tell.
For example, when driving at night with headlights *and* stereo on, the idle speed will occasionally drop really low, causing one or more dash indicator lights to briefly illuminate. In the past week, the Bulb-out light stayed on when this happened, until the car was restarted. (All exterior lights are working.)
The only other time that the engine revs very low is after a cold start; it will idle normally, but once I shift into gear, RPM's drop to about 480-500 for a few seconds before climbing again.
In the light & radio case, the electrical load seems to be the culprit. In the cold start case, the mechanical load of shifting into drive appears to be the case -- unless it is impacting the alternator speed, and output, and thus triggering an electrical disturbace?
WHat I have learned is the sluggish acceleration has nothing to do with the above. In reality, I was (very) low on transmission fluid.
2001 E430 4matic
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black