Allright, I've been having this problem with my 1995 Civic DX 2 door for the past year. The problem doesn't really get worse, but wont go away, and mechanics can't figure out what is causing it.

Once a while my car starts shaking/vibrating when going very steady. Rate of vibration differers, sometimes it is fast, feels like driving over a scarred portion of pavement on a highway shoulder, accompanied by the same noise. Sometimes it is slow, feeling like driving over a small bumps. The condition for the shaking/vibration to happen, is that the car must be going steady at a constant speed, not accelerating/decelerating. If i tap the gas or let go of the gas, it immediately goes away. It also seems that it is most prone to start when going at a constant speed, and running over a small bump - after it feels like you are constantly driving over that same bumb.

There is no power loss/rpm change when the shaking occurs. In fact, I highly doubt it could be related to engine/ignition. I replaced the whole distributor and spark plugs since I had the vibration, and the vibration is still there. It is probably mechanical, but then I wonder what it could be, if it didn't get worse in a year... I had axles replaced with "raxles" a few months before the vibration started happening, and also one of the front LCA's, b/c the balljoint was bad, right before the vibration started to take place.