Hello, I am brand new on here and do not know if what I am looking for can even be done. I have an 85 El Camino that I put a 6.2 ltr in from a 08 Corvette. It has a 6l80E from a 12 Camaro SS. I bought the ECM and harness from PSI Conversions. Everything was fine for a long time. Now it has a terrible downshift coming to a stop. I replaced the transmission and have the same issue. I am now assuming there is a program issue. I don't know where to start. I ordered everything and have connected to the car. I just don't want to start changing thigs. Any advice would be appreciated. If I need to provide any more information I can just let me know. Trying to do this the right way without blowing up my transmission.
Thanks to anyone willing to help!