Open or closed loop idle

What have you had the most luck with? Open or closed idle. My 6395/454 is much more stable after start up in open loop. Even when first starting off the wide band is pretty stable and as soon as closed they fluctuate. Once the flag shows closed it appears to stay in closed whether I have the closed loop idle set or unset. I have looked at parameters that might force open idle but don't really see the ones that might be the right ones. Thoughts?

both mine are open loop. one has way too much valve overlap for closed loop.