Hyundai Repair: 2002 Sonata gls, vehicle speed sensor, speedometer

Question
I'm having a problem where the speedometer just goes down to zero whenever it feels like it, could it be V.S.S.(vehicle speed sensor)

Answer
Indeed it could.  The vehicle speed sensor is a common failure as is wear of the plastic gear on the assembly to which it attaches.  Also check the wiring in the vicinity of the connector.  Although rare, I've seen some cases where the wiring breaks there.