Had this issue a few weeks ago and thought I would share to help others who may experience the same issue. Car started fine and was driving to work, at a stoplight 20 minutes into my drive the car started to shake (I was near train tracks and actually thought that there may have been a passing freight train). When I reved the engine it seemed to go away, but at idle the whole car was shaking pretty bad. After searching the forums and seeing that it could be a number of possible issues I was unsure how bad the issue may be. After starting the car to begin drive home the check engine light went on. I brought it to a local trusted shop and the next day they told me it was a buildup of carbon on the EGR valve, they cleaned it and everything was back to normal. $90 bucks later and I was a happy camper. Hope this helps someone out there that might have the same issue down the road.