Hi Jahwerx:

___The F/A mixture at point of ignition is not being entirely vaporized as you drop in temps. What appears to happen is some localized pooling of fuel (straight gasoline that has condensed out of the vapor mixture) up against the cylinder walls is not burning anywhere near as efficiently as the std. F/A mixture at higher temps. My best guess anyway. Don’t worry; it happens with all ICE’s, SI’s and CI’s alike. Until the intake Air, Fuel, coolant, and block temps are much more tightly controlled; we will always see lower FE with lower outside ambient air temps.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net