Mazda 1993 LX Speedometer issues!

[Tracysmazda]

Hi! I just bought a 1993 Mazda with 99,500 miles on it. It is like new. Couldn’t believe it when I saw it, the only thing is that in the morning (it seems to only happen in the morning) the darn speedometer gets all loopy and starts buzzing so loud you can hear it outside the vehicle! It starts happening when I get to 20 or so miles/hour and then when I’m probably doing 30/40 it is reading 90/100 miles an hour instead! Very strange! What is wrong? Other than this insane buzzing it seems ok… later in the day it goes away…