Hello,

I bought my 2012 F-150 4wd new from a dealer. Starting out It got 21 miles to the gallon. It has dropped over about 100,000 miles to 17mpg. Until I got too old to do it, I ran a foreign car repair shop specializing in high performance Datsun Z cars so I know my way around the wrenches. I know mileage will drop with tire wear but it has a brand new set of tires, less than 1000 miles. All the specified preventive maintenance has been done.I have a very expensive scan tool that can access the PCM, the CCM and the dash bus. Nothing interesting there. Front brakes and calipers were changed last week. No drag.

Any ideas.

Thanks,
John

 

In 2012 we were not being forced to use E15 gas either. So being that you have you have a scan tool pull up the mode 6 data, what percentage of ethanol is the truck reading? I often see 12- 18% these days when you pull the data.

 

Thanks for the reply. I hadn't even considered the gas mix change. More specifically I wasn't aware of E15. Thanks again.

I kinda grew away from cars as my back tightened up with and arthritis started kicking my butt. I returned to my first loves - nuclear and electronic design engineering.

Again, thanks for the helpful reply. When it cools off up here in the mountains, I'll dig out my tool (!) and see what it says.

On a hunch, I checked it mathematically. 21 mpg * 0.85 = 17.85 mpg. That's almost exactly what I'm getting.

I assumed the 21 mpg already reflected E10 gas.

Next time I fill up, I'm going to buy a tank of E100 and see how things change.


John

 

Nukes.....pfff . Former USN here, nuke machinist's mate/SS on a boomer.

I'd found the same mileage differences here where I live between (back then) "summer" and "winter" gas supplies. In the summer we had 0% ethanol and fuel mileage increased 2,3, sometimes 3.5 mpg. In winter with 10% ethanol it dropped back down again.

 

Try E0 instead.

 

OK, I woke up this morning feeling good so I dug around and found my scan tool. The current ethanol reading is 9.8%. Thinking back, I can't recall seeing an E15 sticker on the pump. Tennessee, with the exception of Nashville, Knoxville and Memphis has great air. I have a high volume air sampler which uses a vacuum cleaner fan to suck prodigious quantities of air through a filter. In my world, we cut a round piece out of the filter and determine how much radioactive particulate is in the air.

After a 10 minute sample in Chattanooga, the filter is dark grey, almost black with crap. Run the test in Tellico Plains (pop 200 in SE TN) and the filter is still either white or it has a yellow tint during pollen season.

Anyway, no E15 here so that doesn't explain the loss in mileage.

The OEM tires lasted 80,000 (!) miles. I started to buy OEM again but I just could not stomach the nearest dealer's $100/hr labor rate. So I went to an independent tire dealer and replaced all 4 skins with the highest mileage tires they offered. No change. I'm still going to run a few tanks of pure gasoline through the truck to see what happens.

Thanks again for the assistance.
John

 

Well Neon John, I like everything but the Gas mileage on mine, but I also knew it would be bad when I bought it. I do get 16 on a really good day. I get 1 to 1.5 MPG better if I stay away from Pilot gas and run Exxon or Shell.
Just a thought, have you changed the plugs in your truck. Mine picked up better than 1 MPG on the freeway when I did the 16 plugs in mine.
BTW, Hello from the north side of Knoxville, If your in Tellico Plains I go through there every time I go to the Skyway and the Dragon in my Mustang. Skyway is a much more of a car road than the Dragon

 

I was thrilled with the mileage I got new. I have a friend who bought the same truck at the same time but got the turbo 6 "for the mileage". I talked to him yesterday and he's even worse off than me.

I changed the plugs 10,000 miles ago. The old plugs looked perfect and I noticed no difference afterward.

The only other thing I can think of is maybe the O2 sensors need changing. On the scan tool the main one in front of the catalyst is cycling about once a second like normal. I can live with 17 I guess. It's just that I gotta know why.

Thanks
John

 

Clean the intake air sensor(s).

Since no engine information was provided ...

If it's an EcoBoost has 3 MAP sensors ...
..
All others ...

Clean the MAF.

HINT/TIP: Put your complete vehicle information (year, model, cab, trim, engine, wheelbase, _x4 drive, mileage, modifications, etc., etc.) in your signature -OR- provide it in your posting(s).
.

 

Thanks for the MAF suggestion. I hadn't gotten to that yet in my thought process. I have the 5L V8. I didn't explicitly say that but from an above post of mine:

"I have a friend who bought the same truck at the same time but got the turbo 6 "for the mileage". " The engine I have is evident.

 

Nothing is evident (or assumed). Just the facts.
.

 

I believe in 2012 Ford offered 4 different engines in F150's. 21 MPG is high you probably have a good drive, moderate speed few stop lights. I could see a slight increase in traffic or an additional light or two making a drop. My other thought is changes in fuel chemistry, wheel bearings and general drive line wear add it all up.

 

[QUOTE=gDMJoe;19378961]Clean the intake air sensor(s).


This and the throttle body also.