Quote Originally Posted by SnakeyesTx
The only code I get is O2 sensor which was recently replaced. The O2 sensor heater relay was replaced as well. When the engine stalls, I can restart it easily. I'm really thinking this is a vacuum issue here with the A/C recirculator valve thing.
A/C flaps are all driven by stepper motors on the E34, there are no vacuum motors used for vent door movement.

Could be a bad fuel pressure regulator, the motor's loading up at idle and flooding out.