Engine goes off in stand and sporadically no power

Hello together… I’ve been having an annoying problem for a few weeks now. And when I’m on the road normally, my V40 has some sporadically the problem that it suddenly goes off when I’m idle. BUT as long as I’m roll and over 30 kmh it stays on. Only below it goes out, I say, while driving the clutch, it goes quietly into idle. If I come to a traffic light and brake then it goes from so below about 30 kmh. Strangely I know that I also noticed that if he has his “phase”, he also has no more power… Ich möglich das möglich? So rattern does the thing now for more than a year… Actually only in idle run… The noise is a bit more irregular in the last time and partly it has to do with the variable camshaft adjustment.