Unsteady speedo at 80mph+

I drove to Albany today (about 200miles) and did about 85mph both ways…so what I noticed was this:
The car has really high rpms at 80mph (4000+)
And the tach sometimes moves down 3 or three hundred rpms with steady pedal pressure then come sback up. Also the speedo independently moves up and down a little too (5mph or so) on level road with the pedal not moving, even with cruise on.
Any idea why? or is this just typical? thanks! :hmm:

I know what may be wrong with the spedo, same thing I have, the cable looses lube and makes the needle kinda shake, dont know what would make the tach move aorund on ya though.