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New to the site and couldnt find any threads that talked about mileage this bad. Also new to my 2011 f150 ecoboost 3.5l v6 Lariat Screw without any modifications (that I know of) and with a bed cover. Filled up on Thursday night, drove about 4 hours of city, and about an hour highway total over the weekend and its now Sunday and I'm at a 1/4 tank. Currently getting 12.0 mpg city with a very light foot. Recently took a 600 mile road trip and got about 14.8 mpg, but I cruised at 85 and I hear mpg drops off over 70 so Im not too worried about that. I'm going easy on the pedal and Im getting maybe 1 mpg more than when I normally drive it. In stop and go traffic the truck also shifts at really low rpms. Driving through town I never get above 2k rpms but im almost always in 4-6 gear. Coming off a light I'll hit 6th by 40 mph or so but when i have to slow down i stay in a higher gear and it sounds like the truck is bogging down. Could the rpms cause bad mileage? Am I wrong to think it just doesnt sound or feel right? I live in florida. Its been 50-70 this weekend and I drive by myself or with one person. Havent driven over 70 this weekend and havent hauled anything.
 

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What PM have you done? odometer reading, tires?
 

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are you using real gas? I like 89 or 91 real gas, get about 20 on hwy at 65-70, 18 @75-70. like the other guy said have you been up on your PM (new plugs, air filter, reg oil changes). what kind of oil are you using?i dont see anything on here about how many miles you have just that you got a 2011.
 

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are you using real gas? I like 89 or 91 real gas, get about 20 on hwy at 65-70, 18 @75-70. like the other guy said have you been up on your PM (new plugs, air filter, reg oil changes). what kind of oil are you using?i dont see anything on here about how many miles you have just that you got a 2011.
Currently on Firestone Transforce HT's (LT275/70R18), just bought it and havent looked at the air filter yet but thats next. Oil is getting replaced in the next month but its not necessarily due. Brand new plugs two months old. Odom around 122000. Just using 87 gas right now. Ive been told the right front brake caliper is sticking too. Would that cause any issues?
 

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Those tires are 49 lbs each doesn’t help. I lost 1-2 mpg’s on mine, Need to replace both front calipers and pads (if one goes then other is right behind) Being a lariat is heavier, not sure on your cover but mine is 85 lbs, did you change out your plugs? If not double check, replace air filter These are just some things that can cause lose of fuel mileage, especially the calipers (is one side hotter than the other?) there’s a start
 

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Those tires are 49 lbs each doesn’t help. I lost 1-2 mpg’s on mine, Need to replace both front calipers and pads (if one goes then other is right behind) Being a lariat is heavier, not sure on your cover but mine is 85 lbs, did you change out your plugs? If not double check, replace air filter These are just some things that can cause lose of fuel mileage, especially the calipers (is one side hotter than the other?) there’s a start
Cover just came off and was replaced by a toolbox so im sure the extra drag will hurt the mileage. The gyt said one tire was getting warm because of the caliper rubbing. What do the tires have to do with it? What do stock tires usually weigh? Ill check air filter.
 

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Cover just came off and was replaced by a toolbox so im sure the extra drag will hurt the mileage. The gyt said one tire was getting warm because of the caliper rubbing. What do the tires have to do with it? What do stock tires usually weigh? Ill check air filter.
How are you determining milage? If going by the truck calculations do a tank to tank ck. and calculate it by hand. Also ck. accuracy of the odometer w/ a measured course of say, ten miles by using hwy. mm posts. There has been discussion of staying no higher than fourth gear around town so as to keep rpms in the optimum range for the turbos. My 2014 has 3:55 max tow gears and gets 18.2 combined. You probably have 3:70 gears and should do better than me.
Jim
 

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I average 13.5 city driving, but i'm running a tad bigger A/T tires (falken wildpeak AT3's), and I have tuner, AFE stage II intake, and MBPR exhaust. I'm going to have to try and lock out 5 & 6th gear to see if that helps. I've hit 18 mpg on a long highway trip driving slightly above the speed limit. On that same trip the wife drove home and averaged 15 mpg...LOL

Like mentioned I'd check all the maintenance items and especially the caliper if one is sticking, that would definitely contribute to the low mpg's
 

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More importantly,
What truck? Crew cab? Bed length? Rear end?

I have a 2012 crew cab with 6.5’ bed, leveled, 275/70/18 tires. But what hurts is the 3.73 rear end. It wants to keep the revs up at highway speeds for towing, max tow package. At 65 unloaded it will see 18. At 75 unloaded I’m happy with 14. My average is 14 all the time. It’s a heavy truck. I don’t think your doing too bad unless you have a regular cab 2wd xl or something.
 

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How are you determining milage? If going by the truck calculations do a tank to tank ck. and calculate it by hand. Also ck. accuracy of the odometer w/ a measured course of say, ten miles by using hwy. mm posts. There has been discussion of staying no higher than fourth gear around town so as to keep rpms in the optimum range for the turbos. My 2014 has 3:55 max tow gears and gets 18.2 combined. You probably have 3:70 gears and should do better than me.
Jim
3.73 would be worse, keeps engine spinning more.
 

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3.73 would be worse, keeps engine spinning more.
In old-school theory, yes.

But in some circumstances, with these Turbo engines, you just might burn less fuel at higher rpms/lower boost than you do at lower rpms/more boost.

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Discussion Starter #12
More importantly,
What truck? Crew cab? Bed length? Rear end?

I have a 2012 crew cab with 6.5’ bed, leveled, 275/70/18 tires. But what hurts is the 3.73 rear end. It wants to keep the revs up at highway speeds for towing, max tow package. At 65 unloaded it will see 18. At 75 unloaded I’m happy with 14. My average is 14 all the time. It’s a heavy truck. I don’t think your doing too bad unless you have a regular cab 2wd xl or something.
Ive got a supercrew with a 5'5 bed I think. All in all pretty similar. My dads 2006 2500 HD with his vortec got better mileage and I used to drive it longer and I always had a very heavy foot. Im checking the air filter soon, locking out the top two gears, and I just put a tank of 89 in it, so we'll see how it goes.
 

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How do i check and see what I have?
Inside driver side door jam there will be a sticker.

163991

  • 15: 3.15 ratio, open differential
  • 27: 3.31 ratio, open differential
  • 19: 3.55 ratio, open differential
  • 26: 3.73 ratio, open differential
  • H9: 3.55 ratio, limited-slip differential
  • B6: 3.73 ratio, limited-slip differential
  • L5: 3.15 ratio, electronic locking differential
  • L3: 3.31 ratio, electronic locking differential
  • L9: 3.55 ratio, electronic locking differential
  • L6: 3.73 ratio, electronic locking differential
  • L4: 4.10 ratio, electronic locking differential
That info is from Stage3MotorSports.com.
 

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New to the site and couldnt find any threads that talked about mileage this bad. Also new to my 2011 f150 ecoboost 3.5l v6 Lariat Screw without any modifications (that I know of) and with a bed cover. Filled up on Thursday night, drove about 4 hours of city, and about an hour highway total over the weekend and its now Sunday and I'm at a 1/4 tank. Currently getting 12.0 mpg city with a very light foot. Recently took a 600 mile road trip and got about 14.8 mpg, but I cruised at 85 and I hear mpg drops off over 70 so Im not too worried about that. I'm going easy on the pedal and Im getting maybe 1 mpg more than when I normally drive it. In stop and go traffic the truck also shifts at really low rpms. Driving through town I never get above 2k rpms but im almost always in 4-6 gear. Coming off a light I'll hit 6th by 40 mph or so but when i have to slow down i stay in a higher gear and it sounds like the truck is bogging down. Could the rpms cause bad mileage? Am I wrong to think it just doesnt sound or feel right? I live in florida. Its been 50-70 this weekend and I drive by myself or with one person. Havent driven over 70 this weekend and havent hauled anything.
New to the site and couldnt find any threads that talked about mileage this bad. Also new to my 2011 f150 ecoboost 3.5l v6 Lariat Screw without any modifications (that I know of) and with a bed cover. Filled up on Thursday night, drove about 4 hours of city, and about an hour highway total over the weekend and its now Sunday and I'm at a 1/4 tank. Currently getting 12.0 mpg city with a very light foot. Recently took a 600 mile road trip and got about 14.8 mpg, but I cruised at 85 and I hear mpg drops off over 70 so Im not too worried about that. I'm going easy on the pedal and Im getting maybe 1 mpg more than when I normally drive it. In stop and go traffic the truck also shifts at really low rpms. Driving through town I never get above 2k rpms but im almost always in 4-6 gear. Coming off a light I'll hit 6th by 40 mph or so but when i have to slow down i stay in a higher gear and it sounds like the truck is bogging down. Could the rpms cause bad mileage? Am I wrong to think it just doesnt sound or feel right? I live in florida. Its been 50-70 this weekend and I drive by myself or with one person. Havent driven over 70 this weekend and havent hauled anything.
There are a lot of variables withe these 3.5 ecos. They don't like head winds, cold weather, up hill, cheap gas, heavy foot, big loads etc. I loved the power in my 13, but gas mileage was always a sore spot for me. I had a Screw lariat 4x4, 3.55, 6.5 box, e lock rear. I don't think my average was above 13mpg mostly highway at 67mph or less until I was well out of factory warranty and I always ran ethynol free premium from the same place. When I pulled my camper I got 9-10mpg. So I heard a lot of the "If you'r worried about mileage don't buy a truck!" The real kicker was everytime it went to the dealer to be checked the computer would be in "Learn" mode after the dignostics and the mileage would jump to about 17 and even 18. Then two weeks or so later it would fall right back to the mid 13's. I even tried getting the shop to lock the computer in the "Learn" mode
My response was I spent an extra $5k for the eco to get better mileage and here I was getting the same as my 03 Screw KR w/3.73 gears and a weezy 5.4. That left me sour especially when I had close friends who owned the same truck or slight variants that were getting high 18's and some were showing me actual gauges with miles traveled etc that were at nearly 21mpg. All were 4x4's. Ford never had an answer.
MY wife was T-boned at 69k miles and even though the truck looked good and drove well after the repairs I didn't trust it but the mpg was getting better and better. I traded it on a 17 lariat, 3.31 elock, 3.5 eco, Screw, 5.5' box.I don't think I have ever seen the average below 17mpg in the winter with up to 10 min. warm up times. It took almost a year to get the block heater replaced under warranty so the warm up times should be shorter. The truck is amost stuck at 19.2 mpg even with the bed and rear seat packed full for camp. My utility trailer with the 5' ramp seems to hurt the most and it still only drops to about 18 or so. I've regularly checked actual gallons and miles traveled and the computer is really close. I did well on my trade due to the low miles on my 13, but it still cost me about $16k to go from a 13 to a 17 and from 69k miles tyo 11k miles, but for peace of mind and way better mileage I am happy.
All I can say is I have read some articles concerning coking in the heads between #2 & #3 cyl.from cheap gas causing some issues. Enjoy the power and keep an eye out for a different one if you can afford it and aren't upside down in this one.

Swamp
 

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New to the site and couldnt find any threads that talked about mileage this bad. Also new to my 2011 f150 ecoboost 3.5l v6 Lariat Screw without any modifications (that I know of) and with a bed cover. Filled up on Thursday night, drove about 4 hours of city, and about an hour highway total over the weekend and its now Sunday and I'm at a 1/4 tank. Currently getting 12.0 mpg city with a very light foot. Recently took a 600 mile road trip and got about 14.8 mpg, but I cruised at 85 and I hear mpg drops off over 70 so Im not too worried about that. I'm going easy on the pedal and Im getting maybe 1 mpg more than when I normally drive it. In stop and go traffic the truck also shifts at really low rpms. Driving through town I never get above 2k rpms but im almost always in 4-6 gear. Coming off a light I'll hit 6th by 40 mph or so but when i have to slow down i stay in a higher gear and it sounds like the truck is bogging down. Could the rpms cause bad mileage? Am I wrong to think it just doesnt sound or feel right? I live in florida. Its been 50-70 this weekend and I drive by myself or with one person. Havent driven over 70 this weekend and havent hauled anything.
 

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The MPG readout on the dash is notoriously negative compared to actual MPG.

Spark plugs for our engine are constantly misgapped even when "pregapped". Current Ford specs indicate 0.28 is the proper gap.

I would also double check proper tire inflation and a dragging brake should mess with your MPG. More force is reqyured to over come the resistance.

Have you done an DI top engine treatment?
 

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Discussion Starter #19
The MPG readout on the dash is notoriously negative compared to actual MPG.

Spark plugs for our engine are constantly misgapped even when "pregapped". Current Ford specs indicate 0.28 is the proper gap.

I would also double check proper tire inflation and a dragging brake should mess with your MPG. More force is reqyured to over come the resistance.

Have you done an DI top engine treatment?

Found some engineer gauges and data in the dash computer and from the source its saying 11.1 mpg. Air filter was fine but ive got the dragging caliper im pricing a fix for right now. Im hearing the odd shifting is evidencing a bad lead frame. Apparently the truck is in adaptive learn for 1500 miles after the latest PCM recall fix, and Im way past that. The truck will shift, and as soon as it shifts ill let off the pedal and itll immediately upshift when the rpms drop.
 

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How are you determining milage? If going by the truck calculations do a tank to tank ck. and calculate it by hand. Also ck. accuracy of the odometer w/ a measured course of say, ten miles by using hwy. mm posts. There has been discussion of staying no higher than fourth gear around town so as to keep rpms in the optimum range for the turbos. My 2014 has 3:55 max tow gears and gets 18.2 combined. You probably have 3:70 gears and should do better than me.
Jim
Do you also have 4x4? My 2013 with 3:55 gets only 12. I do run 275/65 R20 all terrains. I’ve done plugs 20,000 miles ago. Need to do air filter. Any y’all suggest? I’ll the keep in 4th around town.


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