I also believe your hitting fuel cut, those a/f gauges are junk not accurate at all, i have one but its just to fill in my 3rd hole in my pod lol. You need a wideband like stated if you want a good reading.
Also i would really like to see some videos of this 12.1 1/4 mile run if you do not mind? why i ask is because you still have smic.
If your running that then i should be down there with the stuff i have. Never ran it yet at the track since build.
Here is my vid when i was almost stock
http://videos.streetfire.net/video/b...0eb019e5a9.htm