Suddenly super lean while at cruise

[scheides]

Good question. Voltage is rock solid during the condition ~14.1v.

Also, I've thought that maybe it was the CAS going bad (mentioned above) but while looking at my safc during the condition, it stays rock solid, as does my MAF--no major oscillations that would seem to cause this issue. I replaced the CAS anyways, to no avail.

Here's a trick, though: as I mentioned above, sometimes my tach seems to jump up and down a bit during the condition. However, if I look at the afc, it reads steady. The s-afc is spliced into the ecu harness, but I hardly see how this could be the cause (it seems more likely that the lead going to the ecu would be dead, not just consistantly messed up under specific conditions : 10-15% throttle at cruise, near 3000 rpm).