Just recently my car has been haveing a low idle companied by a low humming noise. It will go down to about 200-300 rpm's then shoot up to 1000 than go back down. I did just change my spark plugs from platinums to NGK v powers recommended in my manual recently. I plan on cleaning the IACV and using some throttle body/carb cleaner on the throttle body, but if anyone has some knowledge on this that would be contrary to my solution that would be great, thanks.