84RX-7

I have a 84 RX7 GSL-SE. When it first starts up it creates a lot of white smoke out the exhaust. It also idol's really rough. Once the car gets warmed up however the car runs without a problem, except sometimes it has problems idoling at a constant speed. It might jump around .5K RPMs when its sitting. For some reason this can be fixed by pushing the clutch in a lot of the times though. Im not sure if these are all caused by one problem or if im listing many different ones. I was wondering if anyone had any advice about what might be causing these problems. The car is stock. I got it smoged a while ago (been over 6-8 months now) and replaced the air filter, spark plugs, cap, rotor, and wires so these are fairly new. Thanks in advance for any help you can give me.