The MIL lamp only illuminates with tested DTC's to do with the Emissions control of the engine. The dealers only check the modules for tested DTC's using SDD and not untested or pending DTC's. If the EMS went into limp mode due to overheating then a Tested DTC would be logged in the EMS.
If you have a diagnostic tool check that the accelerator is sending valid position values back to the EMS.
Nanocom:
https://www.aulro.com/afvb/images/im...013/05/318.jpg
MSV2
https://www.aulro.com/afvb/images/im...013/05/319.jpg
It may be a good idea to remove the accelerator plug and coat the contacts on both the plug and the pedal contacts with electrical contact cleaner. If the pedal readings are constant when you lose power again then you will have discounted the pedal as being at fault and then you can move onto tracing the loom back to the EMS looking for chaffing, shorts etc.
HTH Brian.