i went from 16 miles a gallon to 13 miles a gallon when the cold weather hit up here in michigan recently.any ideas why guys? is it because of the mods i did to my truck?

 

make sure your guel reg is not leaking gas into the vacuum line

 

The mods lean out the air/fuel mixture. When you add cold weather, it can make it worse cause the PCM will retard the timing all the time. You won't notice too much power loss, but it kills the fuel mileage. You need to either put your stock air intake on or have someone richen up the mix for you. You can do the stock intake and a K&N filter if you have one. It will help the mileage and you will hardly notice (well this time of year anyway) that the aftermarket intake isn't there anymore. Remember you have more air coming into the engine with those mods, now it is more air that is more dense causing a quicker burn. The stock intake at this point will "choke" the engine (compared to the airflow now) enough that it will prevent the engine from leaning out.

You can try using higher octane gas but at $3 or more per gallon I wouldn't recommend it.

 

Thats crazy i didnt know the cold weather would hurt it that bad with the mods to the engin. Im going to have to make some changes to mine for the winter when i get it put on.

 

Ask any performance shop about intake mods. They lean the fuel mixture out. Cold weather demands more fuel. Put the two together and you get ****ty gas mileage. Don't get me wrong tho, cold weather kills gas mileage anyways, but 13 mpg seems too much of a loss for cold weather.

 

thanks guys.argon, how do i check if my fuel reg is leakin gas into my vacuum lines?where is it located?

 

had i known this i wouldnt have thrown out my stock intake/air box![:@]Would it help to "red neck" a box aroundthe K&n cone filter?

 

Nah, step up the octane and see if that helps. If that doesn't make an improvement, then like Argon said with the regulator. Did you do the coolant bypass mod?

 

I heard that up north they put **** in the fuel tp keep it from feezing in the lines when winter comes, and that drop the milage. My dad has a civic, he say it happens every year.

 

look on the left side of the engine...under the little top cover..its a small pot with a vacuum line on it...unplug the vacuum line and see if its wet/gassy....you may have to check it for a few days to catch it