Ah! Good question! As I understand it, the wobbling pulley threw the engine out of balance, which the ECU interprets as a misfire situation. The ECU responds by effectively turning off what it interprets as the offending cylinder. This causes more imbalance, and a further bad self-diagnosis of a missing cylinder, so it shuts down another one. It kept doing it until it had shut down 5 of 8 cylinders!