Ok, now I must say this is definatly a new mod to me. Aparently, cars after '96 are equipped with OBD2 in their ECU's, and "detune" themselves after you perform most mods. It uses data from the sensors to detect other-than-stock emissions, and will adjust to compensate, cancelling out the gains you got from the mods
The fix is a way to make the computer "forget" the corrections its made to the engine's tuning, therefore letting you have all the gains out of your mods.

Here's the link to the article, please check it out. It's all explained.

5th Gen Air/Fuel Controller - OBD2 "Workaround"

Is there any truth to this? Has anyone done it? or should I just forget I ever saw it...