The same sequence of events happened to me 8 months ago. I did everything, replaced turbo with a used vf-39 replaced both oil control valves and cleaned all avcs lines. Nothing helped really. I was able to get the codes to go away for 1 month. My big mistake was false hope, after a month of no codes I installed a rotated 30r and now here I am with a topspeed ss1 block. Honestly if I could tell you one thing it would be just save your time and money and get ready for an engine build. Sorry man best of luck I felt your pain.