2008 Chevy Impala LTZ 3.9L Fault Codes P0223 and P0443: Diagnosis and Repair Tips for DIY Owners

I'm experiencing two diagnostic trouble codes on my 2008 Chevrolet Impala LTZ with a 3.9L engine: P0223 (Throttle Position Sensor 2 Circuit High Voltage) and P0443 (EVAP Purge Solenoid Control Circuit Malfunction). The onboard message displays 'Reduced engine power' and 'Service Traction Control,' but no fault codes are shown on the dashboard. I have already replaced both the gas pedal sensor and the complete throttle body assembly, including the purge solenoid. Despite these repairs, the issues persist. As a DIY enthusiast with limited budget, I'm seeking affordable troubleshooting steps or potential fixes to resolve this problem without relying on expensive mechanic services. Any insights into possible causes or solutions for P0223 and P0443 in this model would be greatly appreciated.