I am no mechanic but, I have been selling Ford parts for a very long time and have a good understanding of what they do ..... The O2 sensor senses the fuel to air mixture in the exhaust ... If it senses to much fuel then some type of EGR valve will route that mixture back thru the air box to be burned again. This has nothing to do with performance and has everything to do with emissions leaving the tail pipe. Just simply unplugging it is not the answer. The performance car guys purchase a dummy sensor that always sends a "fake" signal to fool the processor. I am sure our good buddy TNT could explain this way better than I can.