Help Diagnose

[apocalypse1812]

A friend has a 07 5.9 auto, all stock besides an edge cts, airdog, intake and exhaust.

He states that above 2000rpm, the truck bogs down, loses power, and throws the p0148 code.

Rail pressure drops when he presses the throttle above 2k rpms or 55mph.

 

[cumminstech2010]

Change fuel filters?

 

[apocalypse1812]

In progress

 

[Henrybankshaft]

What is the fuel pressure at idle and at wot and at the "2000" rpms.

 

[apocalypse1812]

Fuel pressure or rail pressure?

 

[Henrybankshaft]

Fuel pressure. Rail pressure to.

 

[apocalypse1812]

Fuel pressure unknown. Airdog is brand new though. He says rail pressure will be at 17k and then starts to drop off.

 

[Henrybankshaft]

I'd get a gauge on the fuel pressure.

 

[CHEMMINS]

New cp3.....

 

[apocalypse1812]

I was thinking it was either the CP3, or PRV leaking.

 

[apocalypse1812]

What are some other symptoms that would mean that the CP3 is going bad?

 

[Henrybankshaft]

I'd see if you got fuel pressure first.