All the gauges dropping to zero and then going back to normal is something like a system reset. I use to have that, especially on cold days, when I started my car. It turned out that my battery was defective. It had enough power to start the car, but nothing else got power when it was cranking over, so the whole system would reset (although the stereo never locked, so maybe the dash is more sensitive?). When that happened, my trip meter would reset as well. Are you having that?