2011 Ford Fusion Sport P0223 Fault: Throttle Body or Accelerator Pedal Position Sensor Issue?

I own a 2011 Ford Fusion Sport with a 3.5L engine and recently encountered fault code P0223. The vehicle has approximately 65,000 miles on it. I initially replaced the entire throttle body assembly, cleared the fault code, and completed the relearn procedure. After driving about 25 miles without issues, the MIL and CEL lit up again, along with symptoms such as jerking, surging, stuttering, and stalling. I then replaced the Accelerator Pedal Position Sensor (APPS). After another 25 to 30 miles of trouble-free driving, a minor 'hiccup' occurred, followed immediately by the MIL coming back on. The symptoms were mild for the final three miles home. What should I do next? Could this be a failing Powertrain Control Module (PCM)? Is it possible to replace and reflash the PCM myself with an updated software module, or should I ultimately visit a Ford dealership for diagnosis and repair?