SAFC...A/F Probs

[240sxOwner]

My current setup is JE Pistons, T4 Turbo .60 comp, .58 Turbine...Revhard manifold. I have a Cartec Adj FMU and a SAFC with 270's right now. I have a walbro 255 pump. When cruising down the interstate at low throttle, my a/f's fluctuate from 10.0:1 all the way to 18.0+:1!! During high throttle, the a/f's are fine. The safc seems to have no affect on the a/f's at low throttle. I know my o2 sensor is bad, could that cause this? Maybe the fuel pressure too high? I am getting some 370's soon to put in but i want to fix this first. My gas mileage is less than 14/gallon. Someone help me please...

[KATwo40]

What is the base fuel pressure?

[babowc]

well first..change out your o2 sensor.

is this a wb02?

wow.. rich to super lean...

[240sxOwner]

haven't checked base fuel pressure...i know, i need to....

Yes this is with an AEM Wideband with 4K miles on it (brand new)

[babowc]

how did you foul out your wb02 sensor so quick?

[240sxOwner]

the wideband is fine. The stock o2 for the ecu is bad....

[nelson8708]

replace the stock o2 sensor and then it sounds like you need to adjust your low throttle percentage. Put some 370s on there and lose the fmu and that might fix it.