2012 Prostar with Maxxforce 13

Evening guys,

When our driver drives bobtail he can get the truck up to 78 MPH without issue, when he has a load (78-80K) he can only get to 55-60 MPH. He says the truck feels sluggish with no power but no surging/bucking or codes are present. Anyone have any ideas?

We just replaced the turbo in the truck due to it spewing oil out and losing boost. Well this cascaded into a DPF filter change-out, Air waste gate replacement and finally a bad alternator. So in 4 weeks we've replaced:

EGR hot and cold side cooler unit - due to excessive white smoke and coolant consumption
Recent PM & changed out fuel filters as well.
High pressure turbo
EGR valve cleaned and function checked
cleaned out the air to air (was large amount of oil present)
Boost pressure sensor
CCOS (maintenance replacement only) since we were neck deep into the engine.
DPF filter (new non reman)
3 O2 sensors for DPF filter
Alternator - batteries are good but the alternator wasn't charging.

The truck has just started working again and didn't make a dime for the last 2 weeks. I'm hoping someone @Heavyd can shed some light on this. I've spent about $14K in parts and labor and am hoping this is something simple that may have been overlooked like an air filter clogged or something else.

Any help is appreciated.

 

I appreciate the response.

 

Truck is governed for that speed.