Rough Idle during warmup
 

I noticed that after my car does its 3k warmup routine, it idles pretty roughly until I start driving it. This only happens after letting it sit over night. I even tried slipping it into 1st gear and letting it idle. Sure enough, after about 30 seconds, the idle still gets rough. So now I let it warm up for like 30 seconds only and then drive it gingerly.

Is it normal for this to happen?

Have you done anything to the car lately? I would look into spark plugs, vac leak (lower intake manifold). Does the car run rough when it's hot or at red lights? Ever stalls? It probably doesn't hurt to pull out the plugs and take a look to see if it's sooty or burnt lean. Also, try running a bottle of Chevron Techron or Redline SI-1 in the tank. Perhaps the injectors are dirty. I doubt if that's it though but it maybe worth the try.

It only runs rough in the morning if it has been sitting all night. The car runs great after being warmed up once for the day. No problems at a light or stop once warm.

I have made no modifications to the car before this started happening. I did run some Chevron Techron through about 1 week ago. The only difference I can see is that the Milwaukee winter is coming and mornings are colder. I am leaning towards a vacuum leak because of one other problem I am having. Regardless of the engine temperature, I get a drastic reduction of power over 6k RPMs in 1st gear only. All other gears are fine. Other people have said to look for a vacuum leak for that problem too.