I filled up last night and when I went to adjust my SG I found a problem that I could use some assistance with resolving. The tank miles driven info read 1683 miles. I was unable to find a way to re-set it. After fill up, in order to adjust it to show the fuel pumped (22.07 gallons), I ended up with a -45.9% offset. I re-checked all my settings (engine size, tank size, etc.) and they were fine. While driving I noticed that my instant mpg read out was approximately double of what I am used to seeing for the normal driving conditions I encounter. The trip mpg's were higher than normal as well. Since I depend on my SG I don't think I forgot to re-set the numbers at last fill up. The only other possibilities I can think of are one, the SG needs repair. Or two, it has been affected by the extremely cold weather we are we experiencing here in NW Indiana. Any assistance member can provide will be welcome.