DTS 496 375 hp idle problem.
 

I have a 2006 Mercruiser 496 that idles fine u til I apply a little throttle. Then it dies. If I throttle up to about 1200 rpm it ru s fine. Connected a Diacom reader and idle is only at 579 rpm which is too low. Can the code reading software I crease the idle rpm somehow? Looking for any ideas or expertise. Thank you!