Q: Aftermarket Performance Products - Tuning Problem

Sir, I have a 2006 jeep grand Cherokee srt8. I started to put performance parts on the vehicle recently. I recently tried using a Diablo Sport tuning kit. My jeep was running normally and once I added a tune to the vehicle computer the check engine light came on. Once I put the vehicle in drive it would jerk really bad and wouldn't accelerate forward or accelerate in reverse. Now the vehicle is completely shut. Once I turn it on and try to shift to drive or reverse it won't do anything at all. What I'm trying to figure out is if it's a transmission problem or a computer electronic problem. It never had a Transmission problem before. This issue only started after this modification to the computer. Is there anything that I could do? Thanks for your time and assistance.

My car has 115196 miles.
My car has an automatic transmission.