I am having the same problem. its an 03, I rebuilt the engine a couple months ago. Truck runs great besides 4.5 gallons of oil. I sent the injectors out for flow testing and to make sure they were not cracked. New feed lines, new return lines, new banjo bolts and washers for return lines. Injectors are Industrial Injection 30% overs with 65k miles on them and they all tested within a 4cc variance. Balance rates are within spec. I have added UV fuel dye and checked the CP3 seal for leakaged with the oil fill neck removed. I have sent compressed air through the return to take or in my case lift pump with no obstructions found. The truck has been ran with the valve covers off before the UV dye was added. No leaks found. Also replaced all copper washers and injector body O-rings. New O-rings on all injector cups and loctite. Everything has been torqued to spec per Hanes manual and Identifix. I had all my money on a leaking CP3 front shaft seal. With the rail pressure cranked up to 23,000 PSI via Tech 2, no fuel spray out of the seal on the Front of the CP3. Unpluged FPR as well to see if CP3 was leaking before I got my hands on a Tech 2. I have been through hundredes of forums and tried everything under the sun.... At a complete loss.... Any other ideas? Truck has 300k miles on it, freshly built engine less than 5k miles. CP3 has 300k miles as far as I know. Desired rail pressure and actual are almost perfect. within 100-200 psi. EVERYTHING was built within SPECS of the Hanes manual and Identifix. Everyone says replace injectors, feed lines, return lines, banjo bolts, banjo washers,O-rings and It will fix it. Don't see any problems with any of them. Please help I am at my absolute whits end with this money pit.