2007 XC90 4.4L PO174 code so I’m going to redo PCV

[Paul1963]

I’ve got a 174 code. Now my coils were bad and I replaced them and new Volvo plugs
That turned the light off and the car runs smooth again

However my 174 code came back and it’s been about 90,000 miles since they did the balance shaft job on the engine which means they did everything on the upper part of the engine I have to assume anyway

I’m thinking the PVC hoses are dried and cracked hard as a rock so what I’d like to know is besides cleaning the fuel injectors and giving those new seals as well,..redoing the PCV system
what else should I do in there while I have the upper intake manifold off
And what do I need to order for this job so I have everything at the ready for me to Tear in and get it done without having to find that I need other things later and have to order them and wait for them

So again, I want to know all of what I should examine and replace while in the job and all gaskets and seals needed to do it
thank you
Paul