I was reading the Greg banish book SA161 on fuel injection systems. On page 20 he mentions, a piggyback controller that intercepts and modifies the signals going to and from the factory ECU. I was wondering, something retired people do a lot, why couldn't the host cars engine sensors be used in on ...

How about an interface that will allow me to put an LS motor in my 2012 manual trans Mustang. I want the car to function like factory but accept the LS engine like it belonged there. I'm ready.