2005 Pontiac Grand Prix P0300 Code: Rough Idle, No Improvement After Spark Plug and Coil Replacement

I filled my 2005 Pontiac Grand Prix fuel tank and drove approximately 7 miles before parking overnight. The next day, the car started with a very rough idle and the check engine light was flashing. Using an OBD2 scanner, I retrieved only the P0300 code (Random/Multiple Cylinder Misfire). I replaced all spark plugs, ignition wires, and coils, but the issue persists. I attempted to test the MAF sensor by unplugging it—this caused the engine to run even worse. Unplugging the MAP sensor had no effect either. Attached are screenshots of my scan tool's freeze frame data (Pages 1 and 2) for reference. The vehicle is experiencing a persistent misfire across multiple cylinders, which may indicate deeper issues such as fuel quality problems or faulty injectors. I am seeking advice on next steps to diagnose and resolve the P0300 code in this model.