Cooler weather has knocked my mpg down 2 mpg.

[jimdigs]

I was getting 39/40 this summer. I know thats not that good for a 5 speed stock festiva but I have some piston ring issues. Now I'm down to 37/38. Oh well, still better than most cars out there.

[Eaglefreek]

Isn't that common? I believe there are winter and summer blend fuels. http://newsroom.aaa.com/2013/06/what...lend-gasoline/

[bhearts]

Think about the fuel enrichment on start up in the cold. And the time it takes your combustion fire to warm up your block and coolant. It's all parasitic until you're up to temp, but it still expends allot of energy keeping your fluids warm.

[dalebwilson]

Jim:

It has been unusually cold here in Georgia ranging from the high 20's to 40's. Changing out both of my thermostats to the OEM recommended 192 degree unit from O'Reillys has improved my mileage by 2-3 mpg's. Both my cars are in the 48-50 mpg range and now warm up quicker and the heater is toasty as well. I paid about $6 bucks a piece for them.

[sc72]

Besides the winter fuel being a different mix, you should know that when it gets cold out, the fuel is more dense and you will naturally burn more, ever notice that your car has more zip in the winter months.

[TorqueEffect]

Besides the winter fuel being a different mix, you should know that when it gets cold out, the fuel is more dense and you will naturally burn more, ever notice that your car has more zip in the winter months.

I am sure that also has to do with cold air is more dense, so more oxygen equal bigger bang, but more fuel is needed for that extra oxygen.

[Movin]

colder weather tends to make carbon. Put cleaner in your fuel tank, make a thin tube to fog a can down the intake while idling, use a brass brush and a rag to clean the under side of the throttle body and clean the pcv valve, the hose and the nipple. If you really want to go for it, pull the valve cover and clean under the metal plate and clean the top of the head so that cold oil can drain back to the pan quicker...don't want to pump too much oil upstairs and leave the sump dry...!

I use sea foam cans like 2 in the tank and 2 down the intake while running at idle, sometimes 1 in the oil and ran before I clean. One in the oil may shorten the life of seals. I use a can of walmart carb cleaner for the remaining cleaning.

Its hard to find carb cleaner anymore to blow those tires on a wide rim but walmart brand still explodes just right. Be careful not to ignite it while using large quantities cleaning.

[harpon]

Colder air is more dense- more aerodynamic drag, and usually the air is more unsettled in the winter, so unless you're surfing a strong tailwind, that will add drag too.

Also check your tire pressures- they go less in the cold, so less inflated tires don't roll as well

I've ALWAYS run carb cleaner in all my cars for the past 30 years, and never a clogged injector,
but even more in a winter climate, because the wetter weather forms condensation in the gas tank

also why you keep a fuller tank through the winter, especially if the car sits a lot: an empty tank more easily forms water condensation.
Gasoline evaporates in a car that sits a lot, but the thicker gum components remain- so petroleum distillate injector/ carb cleaner
which actually thins out the gas from the gum, helps balance that out

best place to get it is still Dollar Tree

on the other hand, the extra weight of a full tank won't help the mileage.

[bhazard]

Insulate the engine bay. Block the grill off, upper and lower. Block everything and then remove whatever is needed to keep the fan from kicking on while going down the road. Build a belly pan to go under the engine and such. This is good for both aero and getting to temp quicker and staying there. You'll also get better heat.

[jimdigs]

Wow, great advice from all. Thanks.

[TorqueEffect]

Someone should do a write-up on a belly pan, that or make them to sell.

I am sure someone could make one they could vacuum form up to make a mold for making plastic bolt/clip on pieces they could sell.

I'd buy one. Engines in these cars take too long to heat up. Even my B6 takes about a 5mile drive just to get off the bottom Cold mark and into the normal range, and my workplace is only 5 miles away so that really sucks. lol