I have a buddy that has a 07 just over 100k on it and truck is throwing injectors 1 & 3 contribution with a misfire at idle. He has a air dog on the truck and it has failed twice and after the second time was when it started to intermitently mis. So the question i have is is it worth going after just the two or should i replace off or atleast pull all and inspect o-rings. Any insight would be apprectiated thanks.