93 Sunbird 4cyl engine running rough

My car is missing, and running rough, and very spiratic It dies when I first put it in gear sometimes.
Once I do have it going, it doesnt die, but runs kinda rough. The biggest problem is when I am stopped, and when I first start to drive.
I have changed all the spark plugs, but its still doing the same thing. I have a distributorless engine.
I have had suggestions from the O2 sensor, to the ignition coil being the problem.
Any suggestions would be greatly appreciated.