Hi Dave, Yes I agree, if you think back (many years) the speed of closing the butterfly was controlled by the way of little gismo's for emission reasons on overrun.
Then we came in to the era of fuel injection and overrun cut off, but you still have the other issues that the sudden closing of the butterfly may cause, such as excess engine breaking and high pumping losses paired with pulling oil past the piston rings, just to mention a couple.
Scopes are vital tools in todays workshop but as we gain more of an in-sight into how the software engineer controls all the different areas of concern, ie; performance, emissions, durability, etc, etc, hopefully we start to understand the importance of scoping known good traces and realising that it will raise more questions.
The more I learn about how an engine works, the more I realise how little I know.