Same thing happened to me LOOSE battery cables

 

My money is on the VR. The volts probably drop while sitting at a red light in high temps. And when you start to move and get air flow over the VR it starts working again. This will go on for a bit and then it will fail completely.

 

Yep. That's what it's doing. Taking it in tomorrow. Thanks for all the responses.

 

Had the VR replaced today. Dealer said recall letters are being sent out now. The new ones are supposed to be fixed. We shall see.

 

Don't do any checks of anything! Take it to your dealer. My voltage regulator failed on a trip to The Smoky Mts. I was able to limp home fortunately.