Engine RPM Variation

I have an 2006 Buick. The engine RPM will vary up and down with in the first 10 minutes of starting. It goes away after that. The car has been scanned and no codes showed up. Any ideas.

Thanks

vacuum leak

How can I find it? Where might it be?

Do some searches and you’ll find instructions.

http://www.cartalk.com/content/puzzler/transcripts/199942/answer.html