On modern motors it is very difficult to determine what causes faults like yours,it could be electrical or fuel related,crank sensor may be worth a look and I take it all your filters are up to date and renewed regularly,did have one of these with intermittent bad starting and it was a wire rubbed through on the engine loom down near the injectors, these would be worth looking at but guessing may get you nowhere and cost money and it may in the long run need to go onto Ford IDS which will have an in depth look at what all your sensors/fuel system/EGR valve are all doing, good luck.
cdc
July 2014
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