Q. Okay, How Does It Work A. The Venom 400 activates at about 25-30% Throttle Angle. When it does it modifies the input signals going into your computer, in particular the Manifold Absolute Pressure and Throttle Position Sensor Signals.
It wont work. anything that creates an effect by manipulating the sensors will get outlearned by the EEC-V. It will discover that the values have changed and start modifying its long term fuel trim to accept the new values as normal and rewrite the tables to get the effect it was getting before. The OTHER PROBLEM is that the Venom uses a MAP sensor, the Focus has a MAF sensor.
as a general rule, anything like this is useless on a focus.