sidi strange revving at idle

[WhiteSv6Ute]

Hi guys i have 2010 sidi sv6 auto ute and the other day when i started my car at idle it revs up and down randomly for a few seconds like from 1000 1500 and then settles and goes away has any one have clue what this would be?

any help would be awesome!!

 

[Silver6]

Not sure if it helps but my IACV (controls the idle, usually adjustable with a screw driver. Just screw all the way back in) kept playing up on my CRX and did the same thing. In saying that though I don't really know much about these engine. I'm just thinking outside the box.
I would be interested to know though. Good luck