Truck is an 03. Twin 62mm, 5.3, 4l60 trans. OS 12593058. By the Tutorial list, I should be Full Flashing COS 03190003.

My problem, is I cannot find the .tun COS 03190003 to open and flash into the PCM. I have to be missing something so obvious. I have found the .calz 03190003 in the "Custom" folder of LS1B, but I cannot open it, or find anywhere to "select" it to full flash into the PCM to complete the tutorial.

I have successfully tuned a TT G8 GXP so my EFI Live cherry was painfully popped with that car. Suggestions?