Check the easy stuff first, to do it pull off the full intake and look at the fuel rails and the plugs around the fpr. Prolly just can loose. Worst case scenario you have to replace a fitting.
Think of it like this, if you lost rail pressure you wouldn't make it home and you would be throwing a code for it. So it is probably the low pressure supply feed. Do you have a lifter pump?
2004 Silverado LT LB7
Moded air box with custom 5 inch Steel tubing, Full EGR delete with fed up pipes, IAH Delete, fed y bridge, PPE Turbo Horn, shortened drive belt, LBZ CP3 running LB7 FPR, port/polish on IHI with rebuild, Batmo Wheel, PPE boost valve, 3.5 inch down pipe, Full turbo back 5 inch exhaust, Airdog 2 165, red head power steering gearbox, Tie Rod Sleeves, Cognito control Arms, Cognito pitman and idler arms, EFI Cory Willis Tunes, all aluminum transfer case, 33x12.5 nitro a/t on 20 inch Rhino lined American Racing Rims, 4 pair high discharge LED lights behind grill and under trailer Hitch, Rhino Lined bull bar, Bushwacker pocket style riveted fender flares painted to match, Triple Glowshift Gauge A-pillar with Boost/EGR/Low side fuel pressure @ lifter pump, LG Tablet by Verizon on flex pedestal running Torque Pro for real time logging/detailed measurement in realtime/gps speed logging, low and hi beam 4300k HID, pump rub kit, aluminum transfer case, @ 325k miles