I hear ya. Well, your post has me convinced that it as something to do with EGR too. Maybe even MAP or TPS. It is definitely some sensor contributing to engine management at low part throttle.
I dont know much about newer systems, but I was doing my apprenticeship when GM started with efi, and EGR only came into play once the engine was at operating temp and in closed loop.
I like the vehicle too. Mine is over 160,000 kms now and no torque convertor issues. At this point, if it goes, I will replace the whole trans myself rather than lose money trading it in for something with similar problems. I'm done throwing money at Ford Credit. My kids will get this car in my will!