Sorry I havn't been back for awhile.
I am fully experienced with this type of issue.
I saw it coming up very often 6 years ago and it was being blamed on transmission shudder.
I got into the same issue and done a lot of rsearch over a year's time to learn what was happening and how it shows it'self.
Very many shops still don't know about this and looked like many dealer shops were not getting it either.
I think now they do.
Anyways, the missing between speed lower and upper limits is the dead giveaway to what is wrong.
The reason is complicated as I indicated.

..
A hint to anyone wanting to test the PCM coil drivers is to cut off a coil socket, solder leads to it so you can plug in the coil driver onto it.
Using a resistance meter, "look" back at he PCM driver.
If you see it open cbances are it's good but if you see less than about 5000 ohms, it's likely about shorted and can over heat a coil and damage it from passing current full time to long.
The other side will have 12 volts on it when the igntion is in "run" as a check of the harness.
If you see any driver with perment low resistance assuming there is no harness rubthrough, it means a new PCM and programing as well as possible coil/s, labor and all. A lot of $ to go with or let the truck set forever or sell it as is since you can't handle this.
The codes you should see from this kind of trouble will be open coil primary code numbers.
Alway hope the coil is open or there is a harrness issue but somtimes it's not
Good luck and great work.
Happy Holidays.