Sadis

I figured out the problem. The previous owner switched the engine and transmission to an automatic but it still has the same ecu...Smh It has an automatic transmission and engine but a 3.9 computer system. Now I have to search for a computer system. Do you know what year mustang would be compatible with my car?? It an 2004 ford mustang v6. I tried to order it from autozone but they said it wouldnt work because they would need the vin number of the engine that was put in the car. I have no idea. I'll try to contact the dealer that sold me the car but since he's sold it he doesn't answer my calls much..