[Dancake]

On some vehicles the traction control systems are controlled by regulating fuel injection on specific cylinders. A faulty injector would mean that traction control could not be managed as efficiently. This would be a possible explanation. That said, the fuel regulation control method is normally coupled with the braking system, with rapid on/off braking being applied specifically to the spinning/affected wheels. I would be interested to hear how the garage conclusively diagnosed the fault though.