hows your trans temps? i put a t-stat inline so she gets up to at least 150 in the winter.
swapping to synthetic gear lube helps too.
also don't forget to keep a real close eye on tire pressure.as the temps fall,tires lose pressure.all adds up.
don't idle.start her up,insure oil pressure and just drive.diesel's don't produce much for heat idling.she'll warm up WAY faster if you just get going.
you can also ditch that economy killing fan clutch in the winter if your not towing.
i never had a working one,but i hear a correctly functioning one,locks up during cold starts.ouch.
oh,don't forget about a grill cover! make your own with cardboard or whatever.block off some radiator is your goal.
i don't drive much,and hardly record FE on winter fuel,because im pretty much always plowing on these tanks,so it would just be a waste of effort.
but iv got a few:
http://ecomodder.com/forum/em-fuel-log.php?vehicleid=5088