Those kind of MPG losses seem typical these days. 10 years ago it seems like I only lost about .7 MPG in the winter months. It seems reasonable for me to assume that ethanol is being used as a winter additive these days. That might be a reason that winter blend is so much cheaper than summer blend and gets worse mileage. Another reason may be today's engine management systems. Cold air is much densor than warm air. Today's vehicles are much better at maintaining the proper air/fuel ratio. It would take more fuel in cold weather to make the proper air/fuel ratio. Factor in a shot of ethonol that is under the 10% threshold for winter de-icing purposes and that could further lower fuel efficiency. The main ingredient in HEET is ethanol. No wonder fuel pumps and injectors don't last as long as they should.

 

After creating this post I am now using gas from a Citgo station that has no Ethanol. My last tank I got 15.2 mpg. That's the best of seen in some time. There was some interstate travel on that tank but no more than 15 miles at a time. The gas definitely makes a difference. I'm going to look around at some other stations to see what my options are. In my town there just are not many stations that carry gas without Ethanol. I had always been buying my gas at Ingles in the past only because it was convenient.

 

Well I put more air in the tires (they were down a bit), changed the air filter, put some additive in the fuel to clean the injectors (Syntek), and gone easier on the throttle... all of that seems to have made a big difference. I won't know until I refuel what my average is, but so far I have done 80 miles on current tank, still around town, but the gas gauge hasn't really moved much... I hope it has given me a true indication so far.

 

Just an update... I'm still not FULLY happy with the mpgs, but it's much better to drive than the Chevy... I might take it to an aftermarket tune-up place, and make sure I have the right oil in the diffs, and engine. I think i am getting 12 city and 15 hwy, and it is really cold out there right now, so that probably doesn't help. I would love to bump it up another couple of mpgs.

 

Scorpion, you are probably seeing all you're going to get if it's been really cold. The 5.3L Chevies seem to get about 1 mpg better than the Ford 5.4L's do. That might be because the GM trucks are lighter than the Fords.

 

If your truck is a 4x4, driving in 4wd mode will also cause your mpg to drop.

 

I haven't used 4x4 much, but both last truck and this truck were half-ton extended cab 4x4s with 4 auto - so should be similar. Greg, the Ford definitely feels beefier and tougher than the Chevy, so I wouldn't be surprised if it was heavier. But it also feels more refined. Love the Ford!

 

Besides winter blends, y'all do realise that the warm up cycle takes longer, from colder nights, thus more time under rich conditions.