Winter Time MPG

[DreamRyder1963]

My drop truck has lost almost half of its mpg recently. It seems to happen on the cold days we have been having. I say this because earlier this week we had a couple of good warm days and my mileage returne but when it got cold again my mpg dropped again. Is anyone else having this problem or have ideas to.fix it? The only fix I can think of is blocking some of the cold air from entering the breather.

[c20pickup]

have the same problem with my 99 Yukon with a 5.7. about 14-15 in summer months, anything below 30-40 degrees and I see about 9-10 tops. kind of sucks and I don't know the reason, might be some kind of winter blend in the fuel? more warm up time sitting idling? you would think it would run better on a cold blast of air rather than warm summer air but who knows. maybe somebody else will chime in

[Carl Spangler]

Two things working against you:Fuel is reformulated in the winter and cold startups. There really isn't much you can do ............ other than storing the truck in a heated garage and run very thin oil.

cheers
JohnG

[Ryan5O]

Maybe try a block heater. I keep mine plugged up all night. Starts right up in the mornings and its blowing warm air before I'm driving out of my neighborhood. We've got low's in the 20s right now. I haven't noticed a change in my mph, but I did start logging my miles last week. I'll have a better idea next time I gas up.

[DreamRyder1963]

I might try that. I am also switching the intake and exhaust one my truck. I am swapping out my high rise for a low rise Edelbrock and going to headers. I am hoping this will give me noticeable improvement for street use.

[hugger6933]

A big part of it is the gas you are putting in your truck. In the winter I think is when they have more Ethenol in it up to 10%and the more that is in the less mpg you get by great amounts compared to say 5%. So if you got 20 in the summer @5% then in the winter you may only get 15@10% if that makes sense to anybody. Jim

[trac209]

IMHO newer cars are the worst for this as the computer tends to over richen the fuel mixture. My DD mazda 3 gets about 80 miles less per a full tank in the winter. My older vehicles tend to lose some mpg but not near as much in comparison.

[68c10airstream]

To all the mileage questions i will say this, as a past ase master tech of 30 years specializing in drivability issues i dealt with a lot of mileage complaints. Here we go, put an oem sourced thermostat in it for 195 degree (that is factory spec), correct weight oil as per engine spec, air up your tires in cold weather, turn of defrost once the windshield is clean (this turns ac compressor off). That's the minimum including grade and quality of fuel. An engine block heater is a great choice, warm coolant = less fuel for all modes of operation. The block heaters are about 600 watts. That's 5 amps. Get with your electrical power provider and ask their killowatt rate and see what it wold cost for 6-8 hours of use, then check mileage improvements and weigh the costs out. Good luck, Brian F.

[geezer#99]

It's all about cold air management. You want to keep your motor as warm as possible and the incoming air to the carb warm also.
Run a higher rated stat to keep the motor warm. A 195 or 205 will work. Use a grill cover (winter front) or cover the rad (cardboard works) to keep the coolant up to the max temp.
For the carb air inlet you need to pull the air across a hot exhaust manifold.
To keep the intake hot you need a functioning exhaust crossover under the intake.
Problem with incoming cold air and a cold intake plenum and runners is the fuel that's been vaporized in the carb condenses back to a liquid state or close to it and those heavy (larger) droplets of fuel just travel right thru the motor without being burned at all. They do burn once they get into the hot exhaust though.
Biggest problem is trying to run on the ragged edge of too hot, too cold with varying changes in outside temps.
It is what it is!
Cold unheated air in is a gas hog in the winter!

[GASoline71]

What style of choke do you have? Electric, heat, or manual? Double check to make sure the choke butterfly in the horn is STRAIGHT VERTICAL when the engine is warmed up to operating temp. You would be amazed at how having the choke butterfly cocked ever so slight will cause a rich condition and eat more fuel.

Gary

[72MARIO]

If it makes you feel any better my jeep grand Cherokee with a 4.0 6cyl lost nearly 1/2 its normal economy on the last tank. With temperatures in the -20-30's

[DreamRyder1963]

I have an electric choke on my carb. It has been working fine but I might double check it. I did try 100% gas in it a couple of times but it caused little to no change in the mileage.