LS3 does not idle

[vstol]

I have a new LS3 427 which has been run and dyno'd. When I start the car it will idle around 1500 then after working the throttle it will pass idle and want to shut off. I have run it about 15 times up to temperature and I have heard it takes the ECM sometime to sync with the engine but you need to be driving it. One thing I find odd is when I put power to the car the throttle body flips open then back to closed, is that normal? Thanks