Is AFR calibrated to a certain ambient temperature? I don't remember going lean last winter. But since the weather has shifted into the low 30s and 20s all of a sudden I'm seeing 12s in boost and I find myself staying out of boost now. Is it normal? I'm running the 2.825 pulley and no FPR mod.... Could it be related to a plugged up fuel filter? I did the fuel pump upgrade just prior to installing the blower (1.5 yrs ago) and haven't ever changed it. Thoughts?