There was a software upgrade done on my 4.2 at the service along with an oil change. My 4.2 seems to run much better with smoother shifting and more power. Has anyone else noticed a change in performance or is this just my anecdotal perception? Does anyone know what this software update specifically does? I was told it was a recall upgrade.

What is your vehicle's build date? Do you know if it applies to all 4.2s?

Had mine in yesterday. I was told they downloaded a new version of the MMI. That wouldn't have any impact on shifting/performance.