What possible sensors could the weather affect? Days like today, (relatively cool, low humidity, lower 70's) the truck runs like a raped ape! Very low smoke, good throttle response, will spin till 3rd gear with only 3/4 throttle and the banks on level 4. Then other days, you can floor it on any level, even 6, and get nothing but a big cloud of black smoke, no performance, and a lopey idle. What gives? Anyone else experience this?

I agree, I don't have any performance mods really, but truck power seems to fluctuate from day to day. You would think the sensors would keep the performance more steady.

I wonder if during days of higher humidity, the water might be condensating, or sweating, on the MAF, causing erratic readings?

Well the cool , crisp, dry, air is way more dense than the warm humid air. It simply will sustain better combustion due to the higher oxygen level in the cylinders..

AFR is the key. with warm humid air, you will continue to dump fuel in and not be able to burn it all due to the lack of oxygen(black smoke) cooler more condensed dry air, u can pack more fuel and air in, burn most of it and make more power

Good point. Damn Oklahoma, not many days here "cool and dry"

fun while it lasts though!!