Occassionally, on a cold start (but not necessarily in cold weather), my 2001 5.4L will run extremely rough. It is not a miss. It is like it's only hitting on 4 cylinders. Feels like the engine is out of balance. After it runs about a minute it smooths out and runs fine. No check engine light. Killing the engine and restarting works sometimes but not always. Has anyone else had this problem?

 

My truck is a '97 4.6 with 65000miles and it just started doing this the other day. It will run really rough shaking a little until it warms up a bit and then it seems fine, but still not quite right.
No check engine light either!
I am thinking about taking it in tomorrow.