Cold start issues - 2011 C250 OM651

[NotConvinced]

Following on from my previous thread - http://www.mbclub.co.uk/forums/engine/199602-engine-woes-erratic-idle-stall.html

...I'm having issues on cold starts. I've already had the fuel pump replaced - problem still exists. Right after the video below was taken I checked for error codes - there were none. It sometimes stalls after cold start, sometimes I get a slight 'cough' every second or so. When the engine's warm it run fine, smooth and no coughing. Any ideas what might be causing it or any tests I can do?

https://www.youtube.com/watch?v=RCAak32gYxM

Thanks!!

 

[NotConvinced]

Happened again this morning and stalled right after start. After 10 minutes I tried again - everything ran fine once it was warm. Any ideas?