2004 Ram 3500 5.9L Cummins Fuel System Failure: P2509, P0148, and P0251 Diagnoses and Fixes

I've been experiencing recurring electrical and fuel system issues with my 2004 Ram 3500 5.9L Cummins diesel truck for approximately one year. The problems began with an overcharged battery on the passenger side, which eventually resolved after addressing the connection. However, shortly thereafter, I started encountering frequent engine stalling—typically three to four times per day—and the issue worsens when hauling loads between 12 and 20 tons. I've already replaced the fuel pump three times, the fuel filter, and the pressure regulator. I also blew out the fuel lines, yet the truck continues to stall intermittently, especially under load, which suggests a possible fuel starvation condition. Each time the engine dies, it throws code P0148—this code disappears as soon as the engine restarts. I've observed that P2509 consistently appears first, followed by P0148 and P0251. Based on this pattern, I now believe these diagnostic codes are interconnected and may be the root cause of all previous issues. Given that this truck is used for commercial hauling, I cannot afford repeated breakdowns. Can anyone confirm whether P2509 is directly linked to fuel delivery or electrical system faults in a 2004 Ram 3500 5.9L Cummins? What specific steps should I take to diagnose and fix this issue? Any real-world solutions or recommendations would be greatly appreciated.