When i start my car (only when it's cold)it searchs for an idle.Up to 1500 RPMS down to 500rpms back and forth,back and forth.Until temp. gets to 180 deg. then it's fine idles at 1000rpms in park,800rpms in drive.I just hates the way it acts on cold start. Any input would be very helpful. Thanks.

What kind of carb and model? what year car? That sounds like a couple of problems!

81 Z28 350 HOLLY 750 VAC SEC

Two things come to mind. A choke that is mis-adjusted, or a vacuum canister / brake booster that has a leak.

Sounds like the choke to me... is it a Holley 3310?

Could be a fuel leak that drips fuel into the carb while its running if it is already lean then each time fuel drips it revs up then back down until drips again?
have you tried plugging all vacumme hoses to see if one of them eliminates the problem could be brake booster, advance or modulator leaking vacumme?

<font face="Arial,Verdana" size="2">Originally posted by NEONGREEN406:
When i start my car (only when it's cold)it searchs for an idle.Up to 1500 RPMS down to 500rpms back and forth,back and forth.Until temp. gets to 180 deg. then it's fine idles at 1000rpms in park,800rpms in drive.I just hates the way it acts on cold start. Any input would be very helpful. Thanks.</font>
The choke is likely your first place to look. It's possible that the heat bypass on the intake has been blocked off. Guys would block them off to keep the carb cool for a performance increase.

i mist the part about only when warming up!