I picked up an 02 lb7. Truck has a slight lope at idle. Mostly when cold then comes and goes. When accelerating im about 10k below the desired fuel rail pressure but the trucks not throwing a code. I have an airdog 165gph but its not installed yet. Wonding if the fpr can cause this and why it is not throwing a code for low rail pressure. I did notice the 2 lines coming off the filter head to the ficm are cracked. Ill be replacing them as well as a new factory filter and rebuilding the filter head. Not sure if the fpr is bad or i have a weak pump or a mixture. Any help is appreciated. Im new to the lb7s but not duramaxs.