Hi there, I've been browsing your posts on benzworld and it looks like I am having a similar set of problems you once had on your 190E.
On my 2.6, cold starts are fine and on the button, but on warm starts I have to crank longer before the engine catches, and sometimes it sounds like the engine is about to stall, but then it wakes up. Then it smooths out and idles fine. From time to time I also hear a strange groaning/gurgling sound from the rear of the car, most likely from the fuel tank area.
In your posts you mentioned you had these symptoms and that you suspected a faulty/ruptured fuel pressure accumulator. Did this turn out to be the case?
Many thanks,
Craig