type44 rough start and rough idle when cold.. CO off? any ideas?

[JordanVw at aol.com]

in the mornings, my  86 5kt usually starts right up..but it idles like crap, 
around 4000 rpm...if i shut it off, and restart, it will idle fine, for like 
one minute or 2 then it will drop back down to 4000 rpm and idle like crap..if 
i rev the engine, the idle will drop so low once rpm's kick back down it will 
stall out. ..  car will continue to do this until its warmed up..   if i shut 
it off after ive driven it, when its warm, the car starts and idles fine.   it 
only has this low idle problem when its cold.    any ideas?  could this mean 
the CO is off?

thanks
chris
'86 5kt....still looking for a good B5