300tdi no power

Hi all I've got a defender 300tdi coming home from work today and my revs died then stalled so tried to start but no luck so cracked the fuel filter to see if fuel was getting through but as I did there was air in there so tightend it back up and it fired but 10 mins later and it happened again and twice more on way home any ideas what could be causing it thanks in advance

lift pump is a common cause though it could be any point on the suction side from tank to lift pump