Buttonmania

Hi all newbie here, hope this is the correct place for this: ref: vectra 2007 1.9cdti The car starts cold after a few turns, if under labour up an incline she stalls. If standing ticking over sounds ok, if I turn off then try to start more difficult and some times does not want to. Get the usual spanner and inspec message. But if I turn back on these lights disappear until an issue again. I have replaced air filter and fuel filter and cleaned maf sensor. I believe fuel pump from tank js working as fuel is pumped into filter housing if turned to position 2. So can anyone enlighten me as to my next move please. High pressure pump, regulator or injectors? Regards Neil