Need help with this issure.

I have a miss at high rpms

I pulled this engine, manual trans, and 4x4 axle and put them in my F350 Majestic motorhome.

156,000 miles on the engine.

Slightly dusted engine with good compression 375-400 (cranking and corrected for altitude).

Has a little bit of a long start.

No smoke on start up unless 10 degrees or colder
No smoke when pulling either.

Glowplugs ...Good
GPR... Good
Checked resistance from IDM to injectors ...Good

History of some ether for starting before I got my hands on it.

I have AE with the ford enhancement. But I am new to working on a powerstroke and new to AE.

ICP ...new
CPS...new
Oil ....new
EBP...new

Installed a pressure gauge to the drivers side upper port on my fuel bowl:
60 psi at idle
55 psi at WOT 2500-3000 rpms under a load
HPOP stabilized pressure is 2750 @ 40% duty cycle


Truck still misses (semi-intermittently) at higher rpm with a load.

Rechecked codes KOEO: None present

I visually inspected valve movement while running (idle).

Did the buzz test when cold....
All injectors sounded the same when tested individually.

Did a cct when not completely warm:
P0266
p0272

Repeated the test at normal operating temperature:
P0266

Torque values on rocker arms bolts and injector holds are good.

Fuel quality isnt an issure since this problem has remained for 5 tanks of fuel.

Any ideas of what I should do next?

 

Checked poppet clearances: all inbetween .002 and .003
Checked coil resistances : all between 2.8-3.0 ohms
Checked all pushrods : all straight
Checked all poppet screws : all tight