Car was running fine. Pulled into a parking lot and stopped car. Realized I needed to move slightly and started up again, didn't want to run, stumbling had to keep foot on gas. Moved car and stopped it, came back a few minutes later and started up OK and ran fine. Later in the day picked up a friend at airport and thought car seemed to be surging very slightly. Drove for an hour and a half and check engine light came on but car was still running OK although it felt like it was surging slightly at highway speed. When I stopped felt like idle was a bit high. Got home and checked codes 2-3-2 & 2-2-1. Cleared codes and started up cold and immediately got 2-3-1 & 2-2-1 which now re-occur starting cold or warm. The Oxygen Sensor is showing a bouncing voltage in correct range on my digital voltmeter. Cleaned throttle body and Idle Air Control and can't find any vacuum leaks but problem persists. What should I check next?