Hi thank you for your question, my name is ***** ***** I am a fully qualified vehicle technician with over thirty years in the trade, hopefully I can help.
There are a few reasons that may cause the problem and starting with the easiest first, I would check the connecting plug to the coil pack, these can cause problems, you should also carry out a compression test just to be sure the fault isn't a valve (but I wouldn't expect this).
If the connecting plugs look good, and as the fault did clear momentarily after a run, I suspect the injector may be at fault. First check the connecting plug to the injector.
There have been problems connected with the injectors and you may be lucky and a new filter and possibly an additive will solve the problem, but if not you may be looking at having the injectors serviced, I would if this is the case get all the injectors done, to be sure.
I hope this answers your question but do please feel free to ask any further details by replying to this thread.