Hey guys,

Just picked up my '12 Platinum SCrew with the 3.5L Ecoboost last week. I have about 400 miles on it right now, highway driving around 70mph is getting me about 18mpg avg. Much better than the 12mpg I was getting with my GMC.

Couple questions -

How long should I expect the break-in of the engine to take before I see max MPG?

Whats the sweet spot for these trucks to maximize MPG on the highway?

 

I dont have the ecoboost myself but from reading on here it should be around 1500 miles.

 

I picked up somewhere between 1.0 and 1.5 mpg around 8000 miles. I've seen other reports that mention a bump at about 5000.

 

Since we all use and drive our Ecoboosts a little differently, it will probably vary a little....but I'd say an average, that takes in the differences, would be anywhere from 5000 - 8000 miles. I really believe mine had pretty much settled in by the 5000 mark. I did see a big jump...like day and night...at around 800 miles when I first had the truck. MPG jumped about 3.5 MPG within a couple of tank fills after hitting 800 miles. I was really worried about the low MPG I was getting before that and went, "Whew!" when it made the jump.

For me, around 70 seems to be the sweet spot...or maybe cutoff would be a better word...for MPG. Anything very much above that and I can start to see MPG degrade. Head winds at those speeds really cut into the MPG too.

Just my experiences.

 

This was on the highway today. took picture in Mpg so it would make sense to me lol

 

wow thats pretty good was that down hill? lol I have only seen that good once and i was doing 55 MPH stuck behind a big rig. i get like 20 by hand calculations running at 65 in my 2012 5.0 4X4 crew cab

 

If he was going down hill or had backed off the throttle, the MPG meter would have maxed out.

My MPG's improved in stages. I always got very good mpg's from the starting gate but it really settled in at around 8500-9500 miles.

 

You should see an increase around 5,000 miles and I had other people tell me with an EcoBoost they saw another increase at 11,000 miles.

I have a 5.0 liter V8 with 6,000 miles and it gets 18mpg in town and 23 on the highway wit a 3.55 rear end.

 

Likewise, I have the 5.0 and 3.55. It gets 23 on the highway.

I used to get around 21 when I bought it new. Now, it gets 23 after passing 5,500 miles.

 

So how fast are you two driving?

 

Going 60, I get around 23.

Going 55, I have gotten 26.5 - and it was flat all the way from Los Angeles Airport to Westminster. That was my best 30-minute gas mileage.

If I went 75, I expect no more than 19.

 

I've got around 4500 miles on mine right now, same engine and gears as you. My best so far, has been 21.3 at 60 mph. At 73 on the interstate on cruise, I'm 18.6. Guess I've got something to look forward to.

 

Mine is just a lowly 2010 scab 4.6l 3.55 4x4 with 30,000 miles on it now.
This was a few weeks ago on a perfect day of 65 degrees. And it included about 10 miles of city driving before hitting I-75 on my way to Frankenmuth.

 

Now that'll make a chicken dinner taste pretty good!

 

LOL that's something you don't hear everyday..