Alex Luft,
Thank you for taking the time to help me out. Since I posted my question, I found on the net a description of exactly how AFM works. The article explained how, in addition to cutting off fuel to the non-active cylinders, both the Intake and Exhaust valves on cylinders 1, 7, 4, and 6 were actually held in a closed position while the AFM was active. By doing that, the non-active cylinders acted like pneumatic springs so there was no net pumping loss from the non-active cylinders and, unfortunately for me, no contribution to compression braking .
On the brighter side, other sources of wisdom stated that AFM was disabled when the transmission shift lever was moved to the Manual (M) position, which is of course how a person would downshift to enable compression braking, so maybe all is not lost after all.
And as we all know, if its written on the internet, it has to be true. 🙂
Thanks again for your help and have a great COLORADO day!
ColoRetiree
