Mind you I have a 4.7L, but even at 0°F it starts and purs like a kitten with no hesitations or misses and idles very nicely.
When the truck's sensors (mainly O2) are below a certain threshold temp the PCM operates in a closed loop fashion sending a predefined approximate air/fuel ratio to the engine based almost exclusively on the TPS. Once the upstream O2 heats up, then the system goes into open mode and the calibrates the Air/Fuel ratio based on the readings from the upstream O2 sensor. The sensor may be fine, but the upstream on our trucks have a heating unit built in so the sensor can be taken up to operating temp faster so the system can switch to open loop mode. If the heated part of the O2 has failed, the system may think after the set delay that it can switch to open mode, but since the O2 is not warmed up enough it can act strangely causing those misses and surges as the O2 is actually struggling to provide the expected reading.
I would definitely look at the upstream O2 sensor. It may not have failed completely but if the heating element is fried it could be enough to explain the symptoms you both are experiencing.
It could also be that the actuall cabling to the O2 has gone bad, and that fixing the wiring can get everything back up to properly working. That being said you can get a new upstream O2 for less than 40$ and it takes a few minutes to replace, which can be done in your driveway provided you have an O2 socket. Also I found that the best tool to remove the upstream O2 is a flexible head long reach ratchet with a "Crow's Foot" like O2 socket. Both can be found at a local Harbor Freight for under 30$.
If ever the O2 is not the cause you will then have a more responsive truck, and maybe a few more MPG's in process. Not a bad investment from my perspective...
My 2 cents
