worse gas mileage in cold weather, does this make sense?

[9threeEX]

Hate 2 resurrect a really old thread, but has anyone found a real cause for this? My CB is in pretty good tune, but its at 210K and the milage really has gone to crap in the cold weather, could the 02 sensor have anyhting to do with it?

[owequitit]

This is normal. Here is why.

1) Denser air (colder air) requires more fuel to maintain the proper air/fuel ratio. Colder temps have a significant effect on density, and thus fuel mileage.

2) When you let the car warm up, it has to maintain a richer air fuel mixture the colder it gets to make sure there is enough vaporized fuel available to burn. Not all of the fuel has time to atomize (vaporize) so they have to squirt more in.

3) Winter gas usually has ethanol mixed in, which reduces its energy density, which results in worse MPG.

4) You may need a tune up. Part of a Honda tune up is a valve adjustment. This can have a big impact on mileage. I have seen as much as 3-4MPG with an adjustment.

5) How do you measure your gas mileage?

[starchland]

also, when the ground is all snowy your tires are spinning more going no where

[cb9wagon]

i haven't heard anyone ask about if the thermostat is working properly. it will run rich till it reaches temperature (ie open loop). the temp gauge isn't that accurate but it should reach almost half way then thermostat should open