I was experiencing the same issue with iDSi on petrol, then I went ahead, removed throttle body, cleaned it since it was already out, removed intake manifold and cleaned it, removed individual injectors and they were badly clogged with 110,000 km on clock, got it cleaned and reinstalled it back and got the tappet adjusted since it was easy as everything was already removed.
Your real issue is clogged injectors but you can get all other things serviced along as these things have to be removed in-order to gain access to injectors so why not service them as well.
People ignore this service on this vehicle because access to it is not as straight forward on this vehicle and that people have little idea about this important service.
I am very positive that this will solve your problem. Remember, this will get clogged again soon if you don’t replace the fuel filter along.