Why does my Rpm needle move up and down when starting sometimes? on 2006 GMC Envoy

Almost everytime I start my car the Rpm needle moves up and down quickly and it sounds like I am giving it gas when I am not. What would cause this.

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1 answer 2 comments
poss throttle body issues do youhave a ck eng light on? if so scan codes and post so we can adv
No the check engine light isn't on.
THAT DOESN'T MEAN ANYTHING HAVE THE LIVE DATA READ