Chriskodaoctavia2010

Hello . I have recently had an intermittent problem in that while the car starts from cold every time there are odd occasions when warm/hot when starting the engine fires and runs for maybe 2 seconds then stalls. The glow plug light then is flashing - normally it comes on for maybe 1/2 second then goes out. - When cold the glow plug light stays on for maybe a full 2 seconds. I attempt to start again and the same thing happens maybe 4 times then it starts and runs fine. I have (a cheap) code reader which doesnt show any error codes. I recently had a cam belt change on my 2010 Octavia 2.0 diesel auto and also a new fuel filter. These may not be relevant but are the only changes in the last few months. Any thoughts?