[ogre73]

Any car will do this. It is the same principle as if you are wearing rubber soled shoes. You have no path to ground, and neither does a car that is sitting on 4 rubber tires...until you make one with your body. Then it discharges.

Technically, it is triboelectric charging that builds up the electricity. You rubbing against the seat, shifting around in your coats, etc. It won't happen as often on a damp day, as the electricity doesn't build as much potential. The shock is when it discharges from the car (insulated to the ground) through you because you have now become the path of least resistance.

Any car will do this, so don't worry, it's not just your car or a Chevy problem.