I think it's the EGR tube - exhaust gas recirculation - seeing all that pipework and numerous sensors with titles such as 'Delta Pressure Feedback EGR' it's no surprise really that the Roadster is plagued with MIL issues, mine was never properly sorted and was a factor in me getting rid after 12 months. A shame really because I had very few other issues with the car, but evey few weeks the MIL would illuminate and require resetting, it did go back to MMC but was winking again within a week.
I had the MIL light on once, down to a "slow" lambda sensor. Williams changed it and fitted an after market one, not a Morgan part. It was implied that the Morgen specified part isn't really up to the job and if another one goes i'd be advised to replace all three.
Talking to a local specialist it seems that the roadster has a high flow cat and sock Ford sensors, when fast acting "racing" ones are needed. Not sure if that makes sense, but it might.
