i get this randomly every week. anyone seen this before? the car still drives while this happens, but both the tach and speedo go bonkers and the radio turns off and warning lights beep. then it goes away 15 min later..

 

Do you have access to a scanner? If so, post if there are any p-codes.

 

lose wire + bumps
check power wire connections to radio, make sure they aren't touching anything else. I had that same thing happen when a little tiny thread of a wire would randomly tap the wire next to it.