BMW: Rough Start, cold test, cold start

Question
I know you mostly work with e30s but think this problem may be a general one. I have a 90 535i and upon starting the vehicle after it has been sitting for over an hour or so, the car will idle pretty rough. It will not stall out ,but after about 30 sec to a min the idling will become smooth and will run fine. If I try to drive before this it will really struggle. Any ideas?  

Answer
Jim,
 You are right, I mostly work with E30's, and most of my experience is with them and their engines.  Your car has the "big six" engine called the M30.  I have very little experience with this engine and its electronics.

 However, your problem could be that the engine is in need of a tune up, or the cold start injector is not functioning properly.  This would explain why the engine runs rough when cold.  Test the cold start injector to see if its getting voltage, if it is, then pull it out and make sure the injector is squirting fuel.

 Good luck,
 Josh