fuel problem kia?

my diesel kia sorento keeps hunting.have cleaned all the system,replaced filter,blown through pipes with them disconnected from tank.\changed tank unit.Still hunts.When pumping the primer a few times it runs swet for short period then hunts.Just crack off any injector just slightly and runs perfect .Fter stopping car for short period teh filter has got air in it ?????

RON hEMSLEY
May 2007