I have a 91 mustang gt with a 93 motor in it with some work done to the motor from what I was told. They said it had a cam in it, 24 lb injectors, trickflow intake, 93 computer and bbk headers. There might be more but I'm not aware of but I sent it into a mechanic that had to use the 93 harness to get this thing running. So the car starts right up but idles up and down and the exhaust smells like gas bad. Anyone have any ideas where to start?