its the starter causinf griesf ive just cured mine, to check, on front of engine behind pump where the water hose connects to block locate the engie temp sender it has 4 wires going into it, now then unplug the connector and try to start if its nearly instant your starter is cranking to low. 2 cures and both cheap 1 vagom change map to auto or 4-motion 2 use a relay and 4.7k resistor on pin 3 to fool ecu its cold but not for the glows it tells the ecu to inject diesel at much lower crank speed. come back when the test is done