2015 duramax

Hello guy im having trouble with my silverado i made it straight pipe cancel the def and now im trying to disable all nox def and egr codes my engine light is of but my engine power reduce come on 3 minutes after i start my truck and every time i turn it of and re start it it will work just fine for 3 minutes then engine power reduce comes back on does any one of yall know what its causing this if i can have some help thank yall

You're going to have to buy a programmer that supports what you're doing.

Can't you disable all of the codes using the MPVI2 and HP Tuning software?