I did check the injectors and number 3 is quite high at 3 and sometimes 4 mmls so in turn number 2 and 4 are -2.Check the leak back on the injectors....both times I've worked on my diesel cars with poor starting from cold (my Jeep and wifes old Golf) is turned out to be excess leak back on one injector which in turn made it difficult for the pump to reach the minimum pressure it required. If that pressure is not reached it will not fire the injectors. The Jeep was really bad in very cold weather until one day it would not start at all. One recon injector and it was back to instant firing. Worth a look.