I will add another observation to this thread concerning the Facet Duralift. It was 16 below here this morning (ambient temperature - not the windchill factored in) and when I stared the truck, the fuel pressure gauge was reading around 3.5 psi after the filter head. Uh-oh, that doesn't look good. I have a blanket heater that wraps around the fuel filter so I turned that on while the truck was warming up. After about 15 minutes, I jumped back into the truck and started off for work. The gauge pressure went down as I used the throttle. When I pulled the first hill, the gauge was pegged to zero and the restricted filter light came on. If I backed off the throttle, the light would go out and I would at least read some pressure on the gauge. The truck ran fine, but I kept the filter blanket heater on for the entire 25 minute trip "just in case". By the time I arrived at work, the gauge was reading 4.5 psi at idle - still not great but better. I buy my fuel (which is winterized) from a know good source, and I add Stanadyne Performance formula at the rate of 4oz. per tank every time I fill up. I do not think the fuel was jelling (I have experiences fuel jelling in this truck years ago and this wasn't it). I am beginning to think that maybe the Duralift cannot cope well with the increased viscosity of the fuel at this temp?