In closed loop, I am getting intermittent Code 44 (Lean) at idle and zero cross counts. Needless to say, a rough idle goes along with this data. The 02 sensor readings are around 360 to 440 mvolts (at idle), it never crosses the 450 mvolts threshold. Fuel pressure is right on 48 lbs. The BLM and INT are dead on 128. I burn my own chips and am not sure if I need to add fuel or swap the fairly new 02 sensor. Shouldn’t the ECM be adding fuel to compensate? Any guidance would be much appreciated.

Is the O2-sensor "ready"? does it start to "react" when revving?

Maybe its not getting hot enough during idle, it should bounce between bigger values. Try a new heated O2 they dont cost very much.

Yes, the O2 sensor reads "Ready" and it reacts when revving. Once revved the code goes away, back to idle and code is back after a couple minutes. I am just a little confused why the ECM wouldn't be adding more fuel to try and correct the problem itself. The engine is running at operating temp (Around 212) and the headers and exhaust are tight as a drum.

so at idle it coems out of closed loop back to open? You need a heated sensor.

No, it stays in "closed" loop. That is why I don't understand why BLM and INT are perfect at 128 and I am getting a "ready", "lean" and 0 "cross counts" with O2 voltages at 360 to 440 mvolts.

Try idle at open loop option and see if you like it.

I am not sure what you are referring to, could you please explain?

Your mask may not support OL idle. It is a flag in my mask(EBL.xdf).

I am using an ARAP.bin and 6E.xdf. I don't believe I have that option. I searched and saw nothing along those lines. Any other suggestions?

post a log file?...but it sound like you'll need a new O2.....

I concur, and w/gta324, not that it has to fall from closed loop, but o2 volts sound stiff & lean esp for your mods. (edited, I think I said it better this time).

Look at prop gain and O2 target values, maybe BPC.
Somehow it thinks it's doing the right thing when it's wrong.

Maybe your starting BIN's were modified for another engine/induction configuration?

Ok, I appreciate the input. I currently do not have the ability to capture the data to share. I will post the data when I can and update you with any additional findings. Again, THANKS!