10r80 and Coyote 5.0 crate engine mystery shift problem 3 and up

Complete crate package with engine and gearbox. ECU with FOMOCo crate program.

It has from the beginning refused to go from 3 to 4 and up i normal driving or in Sport and manualy shifting up.

It will thou get past third gear if coasting in high rpm and you dab the throltle pedal gently. But only 1 time out of 20 or less. And when it will shift up to 4th, it works as it should in higher gears.
No DTCs come up.

We have tried programing out skip shift, no change. We have tested to disable Torque Baset Shift shceduling, no change.

Shift Caracter is in Base and when you put it in Sport mode it goes to Alt1. So that is as it should.

It seems that some value or parameter is not met or sometihing alike and that is causing it to missbehave.

Has anyone had a similar problem ?

Very thankful if someone would have an idea for what we should look for to solve it.

Interesting, do you have an aftermarket interface for logging, especially ECU and TCM limits?