2008 Jeep Grand Cherokee 3.0 Diesel - P0088 Fuel Rail Pressure Too High | Diagnosis and Fix

Hi everyone, I'm seeking help with a persistent issue on my 2008 Jeep Grand Cherokee 3.0 diesel engine. The vehicle was purchased a few months ago with only 204,000 miles and has been one owner throughout its history. It originally ran well, though it had some suspension and brake issues that I've since repaired at a cost of $900. About two weeks after the repairs, the check engine light came on, initially indicating a faulty glow plug in cylinder one. I replaced that glow plug, but as soon as I start the vehicle, the check engine light reactivates and now displays code P0088 — Fuel Rail / System Pressure Too High. The car starts and runs, but it lacks power and performance. I've already replaced both the fuel filter and air filter with no improvement. This issue is very frustrating and I'm at a loss as to what might be causing it. Any insights or suggestions on how to diagnose or fix P0088 in this specific 2008 Jeep Grand Cherokee 3.0 diesel model would be greatly appreciated.