[mwebb]

newer GM products use DFCO as the time to test EGR of course on many of those systems the MAP sensor is just a tag along klingon for the purposes of the EGR test and has little to zero fuel trim authority
i do not see any thing related to that EGR test
in your stuff ? maybe that system is too primitive ?

Originally Posted by Olympiadis

Here is a screen-shot of some of the (stock) DFCO calibrations on my 1991 Chevy Truck.
link for larger photo:

Note that the factory calibrations shown are not very aggressive at all, and during normal driving conditions it is rare for DFCO to engage.

Also, DFCO and DECEL-enleanment are two completely different things.
DECEL-enleanment commands leaner than stoich AFRs during most deceleration conditions, but only functions when in open-loop mode.

Though it is very wasteful of fuel, closed-loop mode maintains a 14.6:1 AFR during deceleration conditions unless DFCO is engaged.