afr at idle is acting weird help please!

[david200095367]

its a 91 kat with a tuned ecu for 370cc and stock maf.

on a cold start i can use the safc II and add or minus fuel to adjust my afr at idle. After i drive the car for a little, and let it idle, the car idles at a 14.7ish afr and then after 5 seconds it drops to 12.3ish. I try to minus fuel and nothing happens. but if i add fuel it gets richer. i tried a stock ecu and just the safc and it has the same problem. What do you guys think it is?

[Craving4Boost]

does it stay 12.3 or does it fluctuate?

[david200095367]

it mostly stays around 12.3 ish. probably moves just a lil.