It appears a custom flash is needed. Often there is debate on the specific details of a custom flash.

I think Deceleration Fuel Cutoff (DFCO) parameters / tables are different, Manual Transmission vs. Automatic Transmission. It would be interesting to compare nearly identical flashes from a specific application, like maybe a 2003 Express Van with 6.0 liter Automatic vs 2003 Express Van with 6.0 liter Manual. Maybe the DFCO comparisons is a waste of time? Maybe nearly identical flashes don't exist for the 2003 Express Van application to a comparison? Maybe the Operating System is different Manual vs. Automatic?

The joys of a custom flash.

dave w