I was going to test-drive the Denali again, drop it in manual mode and see if the idle miss goes away, but I read that V4 mode/AFM does not happen at idle. Add all the negative reviews about the AFM/DOD systems being basically a situation of 'not if, but when', so we're bailing on this Denali.
And because we're now after a 2500, we're also bailing on further digging into what the engine miss is - at least for now, and I apologize to anyone that's read this thread this far only to get no answer because I normally don't let questions I ask go unresolved, but if I come across solid intel I'll post back.
Hopefully, in about a week I'll post a new thread about our 'new' 2500
. While we really loved how the Denali drove, according to the codes it had 3.42s, and the 2500 we're looking at has 3.73s, and hopefully the lower gears will offset the lower performing 6.0, and the truck will 'feel' just as peppy as the Denali did. Meh - even if it is a bit less 'sporty' I'm sure it'll boogie down the road with authoritahhh.