It doesn't seem to be too big of a deal, but sometimes when my car is idling, the rpm's drop below 1 to around .8, and it sounds like something is shaking under the hood near my left foot. Anyone know if I have anything to be concerned about or if I'm just being paranoid? Thx.

 

If you've ever removed the hoses that connect from the throttle body to the EGR valve, I'd check to make sure that they are hooked up properly. If they aren't plumbed correctly the EGR valve will recirculate spent exhaust gas into the engine while idling. This will cause the engine to idle all lopey as if the cams had too much overlap.