I've waxed the fuel filter in my Dodge twice in areas where I bought the diesel (Idaho and Kansas). I feel confident that the fuel up here in Alaska isn't waxing or gelling because if it were, it would definitely show up in the truck and it doesn't. That and it's actually stalled over a wide range of temperatures. I did put a little 911 in the last fill just because I had it in the shop. Unfortunately, I think it'll be a long time troubleshooting/proof of fix due to how much use it generally gets. My current thing though is that I again cleaned out the check valve/vent on the cap. I'm going to attempt to run it in ways that I think will encourage the problem. If it happens this tank, I will then pull the cap off again and look for icing. If it's there, (there will probably be some) I will remove the check valve from the vent, refill and try again.
Interesting side note (I think this is more karma that cause) I have a bottom skid plate. That, of course made getting to the fuel lines in the snow more of a pain. I took it off around the same time I cleaned the vent cap of ice the first time. I had no noticeable stalling issues the next few times I used the tractor. I grew confident and put it back on and trailered the tractor over to my friend's house to snow blow his driveway. I started with 3/4 of a tank or so and it sputtered/stalled around 1/3 tank on a flat part of his driveway......when it was stuck in a snow ditch a little and I couldn't have got the skid plate off easily if I wanted to. In that case I removed the cap and it varied from not having much of an effect to the tractor running ok (this whole time it stayed running, but wouldn't rev and was obviously starving for fuel somewhat). Leaving the cap loose for a while and then topping off the tank returned the tractor to normal ops. - This particular time might've been what RCW mentioned about it just being out of fuel. Bringing it back home I did another driveway on my road and the tractor worked for a couple hours starting with the remaining nearly full tank from my friend's house. Going up my driveway (so level left and right, just uphill) the tractor sputtered/stalled around 1/3 of a tank again. Loosened the cap, detached a fuel line, got it running perfect and drove to it's parking spot where it has been since we started this discussion. The fuel cap vent had icing on it. I find it funny that it's actually only done it when that skid plate is on (just to piss me off I think), I don't see how the skid plate would actually have an effect (especially in this cold weather).