A stock harness will not work with this, it needs the adapter harness which I dont have to make it work. Cottons Performance may help you out with that, im sure its not that much.
I have a complete new TCI engine harness for $250 if you want to change out your stock harness or you can get an adapter harness to make it work with your stock harness, check with Cottons Performance maybe for a price.
Rob