Just wondering if you guys tend to see a reduction of mileage during the winter months? I seem to be down about 2mpg from usuall in the last few weeks. Temps have been around 5 to 0c outside. Now I do need to put some new plugs/wires on, I can see arcing in the dark etc. Im also wondering if i have a bad A/C compressor, wich I know that I do. Will this cause a loss of mpg as well??? Its not hooked up, so it does not cycle. If it was hooked up still it will almost stall the engine at idle. But seems to be fine when just going along for the ride other than some noise. Any thoughts on this. Also have seen some articles about winter mpg going down do to winter fuel and lack of engine temps etc. Any thoughts on these topics?? Thanks guys!!

 

my truck (chevy 4.3L) lost approx. 1.5 mpg here in WNY over the past month or two. Keep in mind that I did put a little over 200 Lbs. of weight over the rear axle, which I assume contributes to the loss considerably.

 

Probably staying in open loop longer. While in open loop, it will run richer to warm the engine up.

Do everything you can to get the engine hotter quickly. Block off the airflow to the rad. Run a 195* thermostat. Direct warm air into the intake.

 

A 195 thermostat won't get it into closed loop any quicker than a 160 or 180 thermostat, since it goes to closed loop at 110 degrees. But, if the thermostat is stuck partially open, it will increase the warm-up time.

Winter formulations are more volatile than summer blends for easier starting. Could be the formulation change.

Used to notice a drop in mileage during the winter every year here until they went to oxygenated gasoline year round.