OkStateFan

I finally purchased a 2014 F 150 Limited and love it. It has the 3.5L V6 with ecoboost. I have gone through one tank of gas now and I am only getting 14 MPG. I have read on other posts that people are getting much better mileage. It has 51K miles on it now.

I can say I drive like an old man so I was surprised to see that low MPG. My wife drives a 17 Fusion with ecoboost and I get around 30 MPG when I drive it and she gets 22 MPG due to her lead foot.

Anyone have any suggestions? I did fill it up this tank with no ethanol gas so I am going to see it that will help.

FX4BullDog

what type of tires are on your truck? Air pressure? City Driving/Highway Driving, Mixture? How new is your air filter? I had put two tanks in my truck so far since i got it (2013 EcoBoost, 58k miles, and a cap), and so far have done 17.3mpgs and 16.3mpgs. The 2nd tank was due to idling with the AC a couple times for like 10-15 mins each.

Ricktwuhk

1) Disconnect both battery cables, then touch them together. Then, reconnect. Drive for a few hundred miles as you normally would, and the engine and transmission will learn your driving style.

2) Buy 87 octane like you did before. All you did on this tank is waste your money.

OkStateFan

It was a mixture of both City and Highway driving, mostly highway. A new truck for me and got from Ford dealership. Has 22-inch wheels and tires are good. A cheaper brand that what I will replace them with but the tires are around 8 (10.2 when new) of tread. Not offroad tires.

Was going to have the tires done with Nitrogen for pure convenience. I have used that on other cars and never have to worry about air pressure changes due to changes in temp.

dlbb

14-17mpg on 2 different trucks. since you bought it used i recommend putting in new plugs and boots, $140 to know they are new and properly gaped. should be .030-.032. you can do them yourself too in about 45 min with a smoke break between sides lol.

fully disconnect the battery before changing them. turn on the headlights for about a min before reconnecting the battery.

the after all the plugs are done, and the headlights. reconnect the battery. positive side first.
turn the truck on but don't start. turn off everything. radio, lights,and ac/heat. not even the fan on.
then start the truck and let it idle for 15min or so.
next turn on the ac, headlights and radio and idle for 5 min.
with the parking brake on and your foot pressing the brake down idle in drive for 5 min. then just drive the truck how you normally do.

this was a kam/idle relearn and reset. it will make the truck learn the new plugs and your driving style.


also i only use 91 oct and full synthetic oil. it is batter then required but no harm on the truck. it is your money to spend on what makes u feel good about how u treat your truck lol.


lil vid to help u if needed.

OkStateFan

Dearlership filled my trank up with 87 with ethanol, that gas station by me has 100 gas for .10 more for no ethanol. I was just trying to see if it made any difference.

The dealership did put in a new battery the day before I saw it. But I will try the battery method as you suggested

OkStateFan

I was thinking about the spark plugs. Have you done them yourself? I have done my share of spark plugs but not on newer cars or trucks. I have also broken one off before and that is not fun at all to fix. For the 150 USD I think I might do that, but DIY or private mec to do it???

Why do you turn on your lights if no battery is connected?

marshallr

4X4 or 4X2? Which axle ratio?

A 2014 with 51K shouldn't need new plugs. Although I've read that the 3.5 benefits from them a little sooner than usual.

To be honest, I don't think you are too far off what is expected. My 4X4 2014 with the 5.0 will get 13-15 for my normal driving. That is some small town and rural back roads. On a road trip 18-19 is normal for me. Most 4X2's will get about 1 mpg better.

Based on everything I've read the 3.5 is usually about 1 mpg less than the 5.0 all things being equal. Don't expect miracles. You might be able to squeeze 1-2 more mpg's out of it. Maybe not.

If the wheels and tires are larger than factory and the computer hasn't been programed for that size you are getting false readings. You are actually driving the truck farther and faster than your odometer and speedometer are showing. And as a result you are actually getting better fuel mileage than you think.

dlbb

the lights are to fully drain the system. same as touching the terminals. lights are just easier. yes i did the plugs and boots on my 14 right before i traded it in lol. once you get the hang of getting the clips open on the c.o.p, and getting the c.o.p up it is easy. and the lil boots just pull off the c.o.p. i used a small wide blade flat head to gentle pry the c.o.p up. just a lil pull up with a lil leverage to get them to pop. the plugs are light hand tighten only. don't torque them. and d.i.y is easy if you have ever changed a plug on a vehicle before. the vid is only a few min long cause it is so easy.

please note the plugs are supposed to be good for 100k mile. but ecoboost are known to eat them and be sensitive to plug gap. every 30-50k will be my interval on the new truck too.

also note that 91 oct will give you 390 or so rated hp vs the 365 or so on 87. it is recommended for towing. but i just use it all the time. i feel like if i take care of the truck, he will take care of me. my 14 totaled a 740 that snacked on the back. but we were fine and he was repaired lol.

bassJAM

I think a plug change is a good idea too, and just get the Motocraft plugs. Spending more won't really help anything out. And 87 octane is just fine as well.

I took about 6 weeks of driving my truck before my mileage started getting better. I think getting decent fuel economy out of the eco-boosts take a different drying style than in a N/A truck, and it took me that long to change my habits. I have a 60/40 highway/city mix, cruise on the highway at about 75, and typically get between 18-19 mpg now. That's calculated, my dash gauge is about 0.5 mpg optimistic every tank.