I was wonder what that outlet plug does on my d15z1:



There is a cord that came with the car. One end plugged into the motor and the other end is a 3 prone plug to an outlet. Not sure what it does so i haven't used it.

 

That is an aftermarket block heater, used to preheat the engine for easier starting in extremely cold weather. The heater would be left plugged in to AC power all night while the car is parked.