Injection Control Pressure (ICP) is HPOP pressure. And the system is only designed to run at 3000. 4000 is gonna push o-rings out, float the poppets in the injectors, etc.

Detune the truck and see what it runs at. If it still says it's runnin that high, the ICP sensor is probably gone. A sure way to tell is to unplug it and look for evidence of oil, if there is any, the plastic diaphram in the sensor has ruptured.

But they can be bad without rupturing.

Either the tune or the sensor is causin the lope.

I tell people that the only stupid question is the one you are afraid to ask. The ICP is the injection control pressure sensor. It is the one that tells the ECM the hpop.

ICP is Injection Control Pressure. Injection Control Pressure is the pressure generated within the HPOS by the HPOP. The ICP Sensor, is just that. The ICP sensor. The PCM adjusts the IPR based on what the ICP sensor is tellin it.

ok gotcha, i will look into that tomorrow when it stops snowing over here in northwest CT haha. now that icp sensor is plugged right onto the pump?

No, if you're lookin down at the top of the HPOP res it's in the drivers side head almost parralled to the res.

The IPR (injector pressure regulator) is the part screwed into the pump.

What grady said.

The IPR is a two pinned plug that come out of the back/bottom of the pump and points horizontally back toward the fuel bowl.

The ICP sensor is a three pin plug on the drivers side head.

Updates??

still woking on it, dont close this out i will update in the next day or two.

Please update.