Fuel economy tank when the weather got cold?

[OmniGLH]

So we've had a pretty mild winter here in Chicago so far. My wife had knee surgery back in early Dec so she has been driving my truck (since it's an automatic) and I've been driving her car (a manual.)

 

Finally yesterday I got my truck back (whoo-hoo!) as her doc cleared her to drive stick again.

 

And for some reason, the mileage has tanked on it. I used to average 18.5-19 with it, commuting (~60 miles each way, half expressway @ 70mph, half in stop-and-go)... and it's down in the high 14s now. When the wife was driving it, the DIC showed she was averaging only 13, which is crazy... I figured it was her lead foot. Well, it WAS, to some extent, as I'm doing better than she did. But I'm only in the 14 vs. ~19 where I used to be.

 

The weather is cold now... IMO that's really the only difference between early December (when I last drove the truck on a daily basis) and now.

 

I don't recall if last winter was bad like this or not, though last winter the truck was still brand new and I likely would've attributed poor mileage to break-in.

 

Anybody else seeing this?

[newdude]

Cold weather, longer warmup times and winter blend fuels.

[15 Z71]

I noticed that on mine also.

[CptMcSaug]

Same here but once that 6.2 gets warm it loves the denser air. This truck moves out

[ewbldavis]

Mine tanks. There is a noticable difference with winter blend, then it tanks more with colder temps. I averaged 13.5 when it was below 20 for a while.

 

Coworker's egoboost also tanks. His theory is reasonable - cold fluids = thicker; more work, etc.

[TJay74]

Yep, colder air means the ECM is adding more fuel, then add in winter blend and longer warm up times and it will drop the MPG in a hurry. My 6.2L used to be a solid 20-21mpg truck, now I am lucky to touch 18mpg.

[robvas]

Yep, colder air means the ECM is adding more fuel

More air and more fuel make more power so you don't have to give it as much throttle. You don't magically use more gas because the intake air is colder (and denser) which is better for power anyway!

[Jordan18]

I expected mine to drop more than it has. I had a few 500 mile trips over the last month (highway with crappy wind conditions and blowing snow) in -8 to -15 degree F (-15 to -25 Celsius) and I am maintaining at least 18 MPG, with shorter trips (50-100 miles) getting 20-21 MPG. In the summer I get 22-23 MPG average.

 

I drive slightly over the speed limits all the time so I am not babying the truck. Keep in mind this is also a 6.2L. Like McSaug said above, 6.2L seems to like the denser air as this thing just goes.

 

I fuel up exclusively at Shell as I notice further fuel mileage losses with other stations, just a side thing I've noticed.

[Txjose]

Here is my difference from summer to winter gas avg

 

 

Sent from my Note 4 on Tapashit

[Imcrazy]

Yeah mine is the same way especially on short trips, longer drives the warm up time is absorbed more.

[toolmiser]

Mine also has a big drop. I did figure out that my tire pressure also dropped 4-5 lbs, so I filled them and that helped a little. We also had -10 degree weather.

[OmniGLH]

Cool thanks guys

[rshad]

Winter blends plus if you use the remote start that really kills the mpg.

[akkrezz]

My MPG definitely went down some when winter came around. I got my truck in the fall and when winter came I started averaging around 14. When i go on long road trips though I'm averaging anywhere form 18-20 mpg in auto, driving through snow. And the temps fluctuate between -20 to 20 above from where I'm driving to and from. Cant wait to see what i average in the summer time.

 

And BTW my trucks a 6.2 8spd

[15slvrDbl]

Yup mpg dropped like a rock. Mine is due to the remote start and warm up mostly. I drive my kids to school every school day so I let the truck get warm. If it was just me I would considerably lower the warm up time.