no, what it does, is trick the computer into thinking it is colder outside than it actually is, and it affects the car all the time.
The computer responds by adding a bit more fuel and advancing the timing some. This has some good effects (like the advanced timing) and some bad effects (like the car will run even richer, and the effects that go along with that, and an increased chance of detonation under certain circumstances)
Personally, its too haphazard an approach for me, but if it floats your boat fine, but I would absolutely NOT recommend this for a forced induction car.
FYI, I am currently working with several folks to make a self-reprogrammable "chip" available that will work for the SVT. Note, this is not something I would make money from, I simply want one to be available for me, so I am getting the proper stuff together for people to make it happen.
A word of cuation though, this type of chip is something that only people who understand engine controls, etc. should really be fooling with, because there is the possibility of damaging your engine if you do something stupid. I will keep everyone posted as things progress.
