I've heard that term of a "vi brator" used to describe a VW gauge dampening device. If I dig deep enough I may still even have one in the shop attic and if I do I'll take the thing apart to see what's inside. The idea of using some sort of a "vi brator" (I'm thinking of those big cans used in early car radios and also called a vi brator) in that application on a gas gauge simply makes no sense to me, so it must be something else inside.
BTW, those early car radio vi brator were a 6 volt relay set to open and close at a specific frequency (somewhere around 400 hertz, I believe) that turned the 6 volt DC input into 400 hertz simulated AC (square wave) that was then increased in voltage by a transformer into higher voltages needed for the vacuum tubes used in the radio (usually 45 - 250 volts).