E78 - 2011 CHEV SILVY 2500 6.0L 6L90E (12640467) - STOCK FILE.ctz

I'm having a weird issue.
When I go to edit the file, the truck won't start.
It only does it when I edit the Engine Calibration. I've tried just changing other parameters in the file and the truck will start and run without issue. As soon as I change 1 degree in one of the spark tables, or fuel tables, the truck will just not start. Flash the stock file back in, starts up right away!

Any help would be appreciated!