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.

 

you might just need an aligment. Also check your Tie Rods those can also be bad. But i would start by getting your car aligned

 

Make sure your suspension and driveline bolts are tight. I'd start there.

 

alignment was done, shaking didnt go away

 

Motor mounts?

 

The mechanic said one of the mounts is slighltly ripped, but shouldnt be causing problems

 

no, rotate you front and rear tires, i almost bet you need all new tires.

 

but if the tires were bad, wouldnt the vibration happen all the time? plus, the vibration started back when the front tires were only a few month old. and also, the intensivity of the vibration differs every time, sometimes its like 10 vibrations per second, sometimes its 1 vibration per second.

 

id guess u need new tires...the different vibrations doesnt really make a difference or the fact that it doesnt happen all the time...i had an identical problem and when i bought new tires for the car instant fix

 

could be bad inner or outer tie rods. have those checked.