An engine control system for an engine, the engine control system comprising: a first input configured to receive a first input data value relating to a first engine parameter, the first input data value being one of a first plurality of possible first inp...

The method involves detecting exhaust gas sensor signals upstream and downstream of the catalyser in an engine controller, which sets the air-fuel ratio to a predetermined value based on the upstream sensor signal in closed-loop mode. If the ratio deviates...