Vibration at Idle

Hello All,
I have a 2004 CRV EX with 43,000 miles. I bought it Certified Used last November. I travel on a local highway that has traffic lights. When I stop at a red light, I feel the vibration of the idle in the steering wheel and through the driver's seat. I believe some of the vibration is the engine fan clicking on.
Yesterday I took the V to my mechanic for an oil change. He told me Im feeling the vibration for two reasons. 1. The V has unibody construction so it's very rigid. 2. There is no insulation on the underside of the vehicle. Any feedback from my fellow owners on this? Thanks.

I get the same thing if I run cheap fuel it gets worse but it happens I saw a saturn today that was idleing so rough its antenna was shaking violently.

A check of all the obvious first - is the motor misfiring, idling rough, any drivability concerns ?
* Valve clearence is always good to check.*
I have also found a few 02-06 CR-V with a bad front motor mount cause a vibration.
Hope this helps - keep us posted ....
Barry B