Pud, Isnt the crack sensor connected to the coils ?
Where are these coils you speak of?
I have 4 theories though and shall list them,
1, I agree that the most probable cause is the crank sensor and when youremove the old one ensure you get the o ring out, it lives on the back of the engine just under the starter motor. easiest access is to move the diesel filter out the way and reach down on the 20V.
2, Glow plugs, unlikely they've all gone together but if the engines earth isn't there then that would answer it, check the earth strap to the gearbox and that the battery terminals are tight.
3, Contaminated fuel, you mentioned this first happened after filling up, I doubt it would have affected the car so quickly but petrol or water in the fuel will prevent it running.
4, Timing belt slippage, possible cause being the water pump jamming on these, the reason it fires up when you floor it - your advance rate suddenly brings it back on cam. Highly unlikely though given it started after cooling the first time.
All this means I go for the crank sensor and a code reset because that is the one fault that if the ECU has it logged it sometimes wont let you run the engine.