Just for you to not feel alone, I had exactely the same issue with mine
(98 civic LX, the stock radio).

The bad behavior started about one year ago and I was blaming my wife's
brisk handling...

Three weeks ago I finally bit the bullet and installed an aftermarket
CD player (ordered it from Crutchfield, they really are good), but I
miss the simple interface and huge buttons of the original one.

The radio sits on the bench at work. I am curious enough to try to fix
it; the root cause seems to be the dial itself, consisting in a simple
tachometer. Since the contacts appear to be OK, my guess is that the
phase between them has shifted somehow and maybe a simple reseating
will do.

If I find out more, I'll let you know.

Serban