D13 bad mpg and less power

Its 2015 D13 got 380k and im running midwest to east..I do not idle at night..i have apu.

 

Its throwing out the same code,volvo said its egr cooler,so i had it under warranty and i let them replaced it.Now after two weeks the same code popped out.

 

What are the codes??

 

P04DB00

 

P04DB Crankcase Ventilation: Disconnected Pipe/Separator Monitor

 

My volvo d13 has only 250k miles on it, and the fuel economy dropped from 6.9 to 5.3 mpg. It starts quickly, creates power as before, but has a little vibration sometimes, not all the time, not at low speed, not at idle, just around 60 mph and the vibration makes the nose to jump, it’s like when you drive on a bumpy road. I took it to a Volvo dealership, then to an other and they didn’t fix it. They checked the boost leak, injectors… nothing! I replaced the boost sensors. No codes!

 

did anyone perform overhead on this truck

 

They adjusted the valves, nothing changed!

 

Clogged egr cooler could cause bed fuel average on d13 engine