Am struggling with a mystery.

I have twin 2004 crusader 6.0s. On any start, hot or cold, the engine hunts for idle with wide swings. It settles eventually or if I give it a bit of throttle, it settles back quicker. It also happens when I throttle down in neutral, it hunts a bit before settling down. (RPMS are stable at anywhere over 1k). I changed the MAP sensors with no effect. I changed the IAC valves, it just made it worse funny enough. I really don't want to spend more on parts or buying a scanner. Are there any other usual suspects I missed? These engines perform flawlessly under load...this issue is more being picky but it drives me crazy.
Any ideas? I was thinking about the coolant temp sensors but I am not getting any CEL and the issue occurs regardless of whether the engine is hot or cold.

Thanks in advance.