All good, as it is a common issue..as I just bought my buddies 92' HB and same deal, here/there speedo works, jumps /bounces and so on..but I just bought a tach guage cluster to swap in and so will have to test it out. More then likely sounds like VSS.Vehicle Speed Sensor (VSS) FTW
Get it. Replace it. Floor it... err.. Test it! ^-^
that was my problem as well as thousands of other accord/prelude owners problem
OOPs! post is over a year old!
my mistake ._.;;