The speedometer in my 02 EX sedan (AT) will sometimes shift up or down and then return to the correct speed within a second or two. Normally the shift is about 5-10 mph but a couple times has been as much as 30. It seems totally random and isn't necessarily a constant thing. It's most obvious while cruising of course and may happen a few times within 30-60 minutes. Bumps don't seem to have any effect.

Would this be the VSS or some other sensor? Is there any way to test it. The tach is not effected. Performance doesn't seem to be affected. It's more of an annoyance, but I don't want it to become an issue either.

 

Look in the FAQs for the gauge cluster self-diagnostic. That will tell you if it's the gauge cluster itself that's bad.

EDIT: Here it is- https://honda-tech.com/forums/showthread.php?t=2908290

 

Cluster gauges check out fine.