Damaged engine mounts can lead to vibration and roughness felt in the steering wheel. A rattle in the dash and engine area may also be heard. Replacement of damaged mounts will commonly correct these issues.
Car Problem Reports
Honda Civic del Sol Bad Engine Mounts May Cause Vibration, Roughness, and Rattle
Honda Civic del Sol Problem
Engine Affected: 1.6L 4 Cylinder
I figured it was due to the fact that half my exhaust (at one point straight from headers) rusted and broke off. However I had most of it welded back together and the steering wheel still shakes like crazy at idle. You can feel the vibrations through your whole body, and sorry Beach Boys, they weren't very good.