2006 Volvo D12 no power. Injector or other?

Volvo d12 2006. Don’t know much about truck. This is what’s going on. On cold start the truck runs completely fine. Once the truck warms up it has a lack of power. Almost like it’s in wrong gear or something. It shakes it rides rough hard to explain. Took it to one dealer they pulled codes for egr and said that the wires for egr were cut. Took it to another shop they said it egr codes were present but also had a code for the number 1 injector. Neither did a injector cut out test. Should i take this truck to a Volvo dealer? Because it seems everyone is scared of a Volvo motor

 

Full pm done

 

North Carolina/Virginia

 

What is a loose engine? It has no blow by. It runs fine cold but when it gets up to operating temp then it acts crazy