Armorskids

2017 3.5L ecoboost. Gas mileage when I got the truck with 30k on the odo was 23.9 hwy and 19-20 to/from work which is a mix. The 23.9 was averaging 65 to 70 over many long drives over the summer. It was pretty consistant. Then winter came. I dropped to 13.5-16 to and from work. Similar Long trips dropped to maybe 20, frequently 19 mph. So something seems to be going on. I've now got somewhere around 38k on the odo.
I've cleaned both map sensors, they weren't bad at all but I cleaned them anyway. the first was the one in front of the throttle body. The other on top of the engine near the back. Oil change and new air filter at dealership.
Same gas mileage, no difference. I didn't really expect to see any since the map's weren't dirty. Any suggestions? For all I know, it's an O2 sensor or something that hasn't yet thrown a code bad enough to trigger any warning lights. We've got two auto repair places nearby that we use. The first is a great little mom/pop place, that we do oil changes, batteries, alternators, etc at. You know, the normal stuff. Great family that runs it. However for more advanced work we have a second place that really is more detailed, and you'd trust with more challenging things. Question 1: Can most auto shops read the codes on the 2017 as detailed as Ford? For our 2004 sport trac it was no problem, it's all old tech. But I wonder about the 2017 computer. Does Ford have the ability to diagnose the issue better than the local good auto repair place? More advanced diagnosis capabilities? I doubt the small mom and pop shops can afford to buy all the newest and most advanced computer systems for working on each and every make of new car out there. So what do you think? Does Autozone have the ability to read these codes as easily? That's a big step down from an auto repair place, but they also sometimes can surprise you.
Question 2: Any value in resetting the computer by unhooking the battery? That used to be the common way on older vehicles, but on newer vehicles that may do nothing but make you re-set your radio buttons. Any value in trying that? Or is there another way to reset to original default settings to start fresh?
Just as a side note, I'm so used to working on my sport trac, it was at the perfect height. When I opened the hood of the f150 wow I struggled reaching the battery and air filter. Gotta use a small ladder, which made me laugh.

Thanks Everyone!
--Bob

marshallr

Oil companies change the fuel during the winter to a formula that pollutes less. It also gets lower MPG's. That is a little more loss than typical and there may be other factors going on too, but my guess is that winter fuel is the biggest part of the problem. Some engines seem to be effected by it more than others. I don't have the 3.5, but it is considered a high performance engine and might need the better fuel to work best. I tend to lose 1-2 mpg in winter with my 5.0.

Armorskids

Thanks Marshallr, thanks for the reply. That's a good point and I'm sure it's part of it. And for all I know that's the whole thing. I don't know I've never had a dual-turbocharged vehicle before. From my prior experience, 1-2 mpg was winter gas. Maybe it's nothing more than that, but it seems like it could be something else, too.
--Bob

Jeep4Life

Nice truck M, I just bought a 2014 4X4 SCREW 5.0L, really loving it so far. Here's the pic that will become my new avatar one of these days:

Old Grey Mule

That is about normal MPG for the 3.5 eco. You might be getting more bold with the throttle the longer you own it. It happens.

Ryan_2020

With winter gas, winter tires, remote start, etc. I run about 14.5 mpg during the winter (with a 5.0), and probably more like 16 mpg during the summer, so a 1.5 mpg drop in the winter for me.

(this is on my 'normal commute', I don't do enough highway driving in the winter to give advice on that)

frosty19

I find my ecoboost uses a lot more fuel in the cold, even accounting for the winter gas. Granted it was very cold here but same commute dropped from about 13.5L/100km to 17L/100km.
Cleaned the MAF sensors and replaced plugs and air filter, didnt really change much.

acdii

Is that dash calculated or hand calculated? Many reasons were posted above, but a lot depends on how the readings were reached to start with. I have noticed a 1 MPG drop on mine since winter started.

baddceo

Perhaps this has to do with just different driving habits. You say you got the truck with 30K on it reading a 23.9mpg which in my opinion is way high on the average best you would ever get in this truck i don't care where or how you drive. What you are getting seems more average to me maybe a little low because of the winter gas and the colder temperatures. You burn less gas in the summer providing you don't have your AC cranked way up.

I am light foot and was averaging 17.4 before I changed to level and new wheels and tires. I just filled up and my winter average on that take with the current setup was 16.6. Keep in mind I added a bunch of unsprung weight as well.

Do you carry passengers and/or stuff in the bed regularly that would weight you down?

dont slow down

Have a buddy at work that bought an eco boost and loved the mileage, till winter came. His mileage dropped way down too. He said it came back up in the summer but not to what it was before. This was one reason I opted to avoid the eco boost. Between the weather and the winter fuel I'd say those are your two biggest factors
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