Here are 3 electrical circuits for fooling the computer o2 sensor readings:

http://www.mkiv.com/techarticles/oxy...sor_simulator/

Electronic Fuel Injection Enhancer Manual (EFIE) [4901.99.00.503] - $9.00 : Eagle-Research Store

http://better-mileage.com/memberadx.html

I was going to build the Eagle Research circuit but did the non-fouler mod because it is simpler and less expensive. Maybe it works better and more specific and maybe there is a benefit to both.