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.

by in Mobile, AL on November 13, 2012
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer 2 comments
ANSWER by , November 13, 2012
poss throttle body issues do youhave a ck eng light on? if so scan codes and post so we can adv
COMMENT by , November 14, 2012
No the check engine light isn't on.
COMMENT by , November 14, 2012
THAT DOESN'T MEAN ANYTHING HAVE THE LIVE DATA READ