Your problem is a failing outlet, or a loose connection of the white, or black wire to the outlet. If you are comfortable working on house wiring, turn of the breaker to that outlet, remove the faceplate, check the wire connections with a screwdriver. If the connections are tight, the outlet needs replacing.
 As you are an electrician, I assume you already checked the stuff I mentioned. In that case there is a faulty connection in the molded plug. GM should cover that under warranty, I would think.