Firstly, I would like to know exactly how he is going to measure the timing chain for stretch.
I am not clued up on o2 sensors, but I know my around crank sensors and I'm fairly certain a crank sensor fault would cause you a constant headache, and not just whilst turning right. Afterall, the crank doesn't care if you're reversing, turning, handbrake turning or free falling from an aeroplane... the crank is still turning in the same direction. I guess that roughly the same applies to the o2 sensor, the airflow through your intake/exhaust should not be sufficiently effected by the direction of the vehicles travel to cause your engine to cut out.