My Plus8 with Gems management used to have the MIL occasionally come on.
My OBD meter showed “random intermittent misfire” as the reason. I checked the plugs( low mileage ) , leads, connections on sensors but it would occasionally come back. I switched to V-Power and it stopped. The only time it returns is if I have used 95 octane for a few tank fulls. I have also put a simple heatshield round the cats to help keep them in best operating temp. A single layer of Aluminium with stainless straps, no extra insulation.
Meabh, your MIL is on when the same sensor is the culprit? I doubt it is the MAF. I would concentrate on that sensor and double check the connections, wiring. It might also be worth making some shielding to reduce airflow round that area as it may overcool that sensor?
