Cobra498 tuning

[Cobra #3170]

I have had my engine in the car for about a month now and it is driving me nuts. I have taken it to two autox's to test it and have had to be pushed off course both times because it died in the middle of a run. So far I found that my charging system was failing ( blown diode and burned windings from Laguna last year) and the kill switch has about a 1 volt drop across it even though the car starts just fine. The low end of the EFI map seems to be off also as well as the O2 sensor. The engine makes plenty of power from 3500 up but does not run well at lower rpm which seems to be related to calibration. I am running alpha N and have been told that the O2 sensor can control fuel mixture but am not so sure in alpha N. I have a classic FAST system and it is so rich at low speed it burns your eyes. I plan on changing the O2 sensor next to see if that helps.
I have attached a video of a relatively slow neighborhood drive that shows how poor the low end calibration is. at 2:58 I hit it to about 50% throttle and it goes to 7000 rpm almost immediately (74 mph wheel speed). It is better but still no cigar, does the O2 sensor actually have any influence on air fuel ratios in alpha N on a classic FAST system?
Video
YouTube