[trappedincanada]

I had my E92 experience a similar problem, the same scenario - loss of power and overheating symbol coming on. I had my mechanic check out the car and I we had discovered:
1. The thermostat was ineffective, and I subsequently had it removed. BMWs don't necessarily need the thermostats in African countries with warm climates because we don't have erratic weather conditions like countries in Europe etc.

2. My coolant temperature sensor was broken and that caused the fan to run at full speed every single day which was very frustrating. I had that sensor replaced and haven't had a high temperature reading since.

Best of luck.