Speedometer Jumping

Hey guys,

I was driving my 07 TL-S 6MT home from a long drive this morning & noticed my speedometer would periodically jump between a 40km/h +/- of my actual speed. I wasn't using cruise control & the car seemed to drive just fine. No CEL's/warning lights on the dash either. Car has approx. 181,000km on it as of now & all maintenance is up to date.

Could it be a speed sensor or something wrong with the gauge cluster perhaps?

Any input is greatly appreciated.