Well I blew the factory motor in my 1999 mustang gt quite awhile back. It has the 2.1 KB, 90mm mass air, 36lb injectors, 75mm throttle body, KB BAP and switch chip. I built a 4.75 stroker and put all of the goodies back on including a new clutch, 255lph fuel pump(also running BAP) cat deletes, and MIL eliminators. I started it up for the first time and my wideband was showing it was running super lean. So I killed it and fired it up again and it said it was running super rich. It does this every time I start it, either really lean or really rich. Also it won't idle down lower than 1600rpms. Any ideas?