year 2000 3.0 l dohc turbo diesel - iszuzu trooper - john6665

Hi all, just new here , I have a 2000 3.0 l turbo diesel trooper, it was recalled 2 years ago for injectors, but never really ran perfect after this, however it has got to stage that its like its running on 3 cylinders now, however i had it back at main dealer last week for recall trottle position sensor, so i asked him to inspect same , he told me its one of the injector solenids, but stated this would not be covered by warranty, ? so i asked how much it would cost out of warranty he said around €1000 , I cant afford this, has anyone else had this problem, did isuzu sort it under warranty ? or is it something I can buy and replace myself, i know my round a car ?? all answers welcome thank you