Volvo d13 2012 power loss, SPN 1127, SPN 2659 FMI 18, SPN 3216 FMI12

I hope I will help someone not to loose his nerves and to save some bucks.

My truck didn't had power when it was hooked up with trailer(bobtail had power on interstate, but with trailer after 50 mph it was struggling to speed up, and on lowest hill I was loosing speed), so I stopped to repair shop near my house in Delaware. They diagnosed that I have a leak in air cooler and that was making a power loss problem, so they replaced it(800$parts 300$labor). I had 2 codes SPN 1127 FMI 10, SPN 1127 FMI 18. When I took a truck and after 20 miles I had same problem, so I came back, they replaced boost pressure temperature sensor(80$+70$). I tested it for 40 miles and it was driving normally, but when I took a load I had same problem. So I drove that load from New Castle, DE to Cleveland for about 14 hours because I didn't had speed on uphill's, Then I drove empty during the night to Gary, IN to see another mechanic. Now I had more codes, that 2 plus SPN 1127 FMI 14, SPN 3216 FMI12, SPN 102 FMI 14, SPN 2659 FMI 18
We found that I have a leak between turbo and exhaust manifold, and mechanic was thinking that was causing all the mess. We replaced all gaskets, manifold, turbo and EGR. Tested the truck and we had same problem. He found a code that I don't have in my records for fuel pressure, so he tested fuel lines, replaced a fuel pump and it was still without power. I made a call to @nasriza, told him symptoms and he guide us to EGR valve. Lucky me that Volvo didn't had EGR in stock anywhere, because I would buy it. Next thing that we tried is to put a plug into EGR line. I tested it and truck was driving normally for 15 miles. Then I took a load and after 40 miles I got a code SPN 412 FMI 5, but truck was driving good. I stopped to connect that temperature sensor because mechanic forgot to put it back. And after 100 miles I lost power again. I was thinking plug was lost so I checked it, it didn't moved anywhere. And then I was guessing that temperature sensor was making all that problems, I took that plug out from EGR line and disconnected temp sensor. WHOOOOOOLAAAAAAAA. Truck was driving normally, so I drove back home 800 miles and replaced stupid sensor for 84$. I had never code for that sensor until it was disconnected, I lost 2 weeks in repair shops, and almost 4000$ for parts and labor.... and I needed to go for rehab before I I start driving again....