[Vwdiesel] '86 runs rough when not fully warmed up

[Libbybapa at wmconnect.com]

My '86 NA Jetta has begun developing some sad symptoms.  Starts right up.  
Idles fine, but high idle has an intermittent non regular miss.  When driving, 
she jerks a little and seems to lack a bit of power until she is fully warm.  
The symptoms last until after the water temp is at it normal op temp, but go 
away after 5 min or so.  After that she drives like the little car I know and 
love.  The problem has gotten progressively worse over the last month.  My 
guess: busted compression ring, faulty injector, burnt out glow plug (not really 
likely to me, as I would think it would not idle as well, and even out faster), 
problem with pump.  Any opinions or suggestions are welcome.
Andrew