I wanted to come to this thread to give the real reason Jody doesnt consider the IDM mod as a "must do" for the "normal stroker". During cold start up the IDM can retard timing by up to 27* and vary the Pulse width widely. the PCM runs three different tables of pulse width, inj. timing and tip in, depending upon the readings it recieves from the EOT, AIT1,AIT2, and ECT. This is why Jody also recommends starting the truck in the stock setting. the pressures that are created during those events are tremendous. the IDM fools the ECM into commanding for the higher timing which can lead to TOO MUCH fuel during the injection event for the lower operating temp conditions of the motor.