both my steering wheel and shifter shakes when i'm idling. once the car warms itself up the rpms are low which in general leaves a vibration throughout the whole car. Typical civic stuff. I had a 1990 dx and that did the same, i had nothing done to that car but my 2000 pretty much does the same s**t my 1990 did. Its nothing to worry about. I heard noises one day from it and i looked under my car and my cat/exhaust was shaking rapidly. I got some more hangers and that fixed that problem.