Sounds like your cold start injector or cold start valve. Does she start up better when she's warm? You might also want to replace your O2 sensor if that hasn't been done recently as they do die and cause rough idle/bad mixture issues.
If none of these work, then you start looking at expensive fixes. Good Luck!
-Matt-

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Currently:
1972 350SL Euro 4spd
1973 BMW R75/5
1981 BMW R80GS
1995 FZJ80 with OM606 Conversion In Progress