Hello Doug,
I am sorry that you have zero power in your vehicle now that you tried installing this tune. Unfortunately, I am unable to assist due to the fact that that I am not a technician or an engineer as well as I cannot comment on anything added aftermarket to the vehicle. I would suggest having your local GM dealership look into this issue. Unfortunately, anything added aftermarket has the possibility of voiding your warranty if yours hasn’t expired. If you would like, I could set you up an appointment to have them look into this issue for you. Thank you very much for your time.
Gregory W.
GM Customer Care