I haven't experienced cold weather like you guys have but I have driven on ice coated roads numerous times in all kinds of vehicles and some fairly deep snow a few times over the years .. What you describe as ideal makes me think of a VW Diesel Truck I owned in the 80s except for the engine size and it wasn't a foot off of the ground but I had a Rancho Suspension lift kit on it for awhile.. We don't get the same diesel fuel in the winter as they do up north so starting was sometimes a problem but only once when it was a freaky 17 below 0 F I wasn't able to get one of my other VW diesels to start... It was 90 degrees here today and my AC is on inside the house so you can imagine how hot it is going to be in 2 months.. It is funny but down here we get better fuel mileage in the winter than in the summer and I know that it is the other way around up where you are.. I have a supercharger and very free flowing exhaust that pretty much keeps the check engine light all of the time.. We had some single digit temperatures this winter and I drove for days with the light off I suppose because of the density of the air.. It puzzles me because I have a reflashed ECU and larger fuel injectors but the light was off... I can see why extra fuel would needed to correct for the increased density of very cold air but it doesn't seem to me that it should increase fuel consumption as it does.. It is confusing to me but I have read enough post by people that drive in those hard winters up there so I know it does.

 

YES, CJ already mentioned that. I wanted to know what it was specifically if he remembered.

 

When your engine is warmed it will vaporize gas which burns more quickly( more mpgs) if its cold it won`t vaporize (less mpgs) if you have high humidity (water in air) this is sucked into the engine and you car is forced to burn water( less mpgs). It the cooler days you have less humidity and thus your car burns fuel better, I think you have a cooling system problem also I would flush the rad or replace it.