2002 Honda Accord P0130 O2 Sensor Low Voltage Code: Causes & Fixes After Transmission Rebuild

Hi everyone! I'm having an issue with my 2002 Honda Accord LX 4-cylinder sedan. The vehicle is showing a recurring P0130 diagnostic trouble code (DTC), which stands for 'O2 Sensor Circuit Low Voltage - Bank 1, Sensor 1'. This code appears and disappears intermittently. Interestingly, this issue started shortly after my transmission was rebuilt. I've already replaced several components including the main relay, spark plugs, ignition wires, cap and rotor, the upstream O2 sensor, and the engine-side sensor harness connector. Despite these repairs, the P0130 code persists — it always appears when the check engine light is on, but often resolves itself after a few minutes or miles. When the check engine light is illuminated, the engine idles low and feels rough. Once the light turns off, idle returns to normal and runs smoothly. I've tested the vacuum using a gauge and found it within acceptable range. The battery and alternator have also been checked and both are functioning properly. I’ve heard that the Air Injection Control (AIC) system can be problematic in high-mileage 2002 Honda Accords. Could a faulty AIC unit be causing this P0130 code and the associated idle issues? If not, what other potential causes or diagnostic steps should I consider? Any insights, suggestions, or experiences with similar problems would be greatly appreciated! Thanks in advance!