Engine problems?

Hello all. I dont know much about cars in general so excuse me if I can't explain the problem I'm having in mechanical terms. I was on my way to work today and I noticed after having driven for a couple minutes that the car was 'shaky' at a red light. It would shake and stop and shake and stop and I felt it more when the car was not in motion. I just tried to drive it around again and at the first there wasn't a problem but after a few minutes it started up again. Can anyone please give me an idea as to what this problem may be? THanks

The I5 is not an inherently balanced engine.  It has free movements/vibrations of the first and second order, so it requires additional balance shafts.  When you say shaky....was the engine not up to full temp. yet?    Any check engine lights??  You may need to go to the dealer for a check if it persists and gets worse.  lots of potential explanations, but none an easy DIY fix.
 
Welcome to the forums.

mine does the same thing. most of the time it's smooth and then it will start shaking the steering wheel whe stopped. you can put your hand on it and it still shakes some and then it goes away. mines going in this week for that and some other stuff. will post when i get it back.

Thank you for the responses and the welcome. To answer Doc, the engine light is not on and i had been driving for about 5 minutes or so when it happened so I'm not sure thats enough time for the engine to be at full temperature and I drove for another ten minutes afterwards and I still felt the shaking of the car. By the way, I've had the car since July and I've only driven it for a little over 4000 miles if thats any help. Thanks again. 

could also be some bad gas, maybe water in it or something.  keep an eye on your tachometer when it happens (does the H3 have one?), see if it jumps around before, during or after the shimmy. 

When you go to the dealer perhaps you should tell them it feels like it has a "Miss" or is "Missing".
 
 

My 2007 does that from time to time for no apparent reason then it will disappear as quickly as it appeared.  I won't experience it again for another few weeks, it's totally random.  Good news is...Consumer Reports the 2007 I-5 as much better than most.
 
 

You say "had the car since July and I've only driven it for a little over 4000 miles."  Is that total miles on the vehicle?  I have 6200 miles on my '08 and no such experience.