I have had my '06 Explorer Limited for about 9 months now and the fuel economy has never been that great. When I test drove the vehicle at the dealer the on-board computer said the average economy was 17.1 MPG. After owning the vehicle for two weeks the economy was down to 14.5. Over the course of the summer it went down to 13.5, and now it is at 12.4. The vehicle has 31,000 miles, a new air filter and I run full synthetic oil in it. Almost all of the miles are city driven with no cargo and driving it easy. I realize that it will not get the best milage since it's a V8 SUV, but I know it has gotten better mileage in the past. I could live with 14-15 MPG in the city, but 12's is getting real low. I know new Expedition EL's can average 15 with a bigger motor and more weight.

Any ideas on how do gain some more miles out of this thing?

 

Have you calculated your mileage manually to see if that matches the computer?

Steve

 

A second to the notion of not relying completely on on-board mileage trip computers. They can be off. Your best bet is to just keep a log of every gallon, always fill (preferably same location or at least with vehicle always at same angle) - don't just "put in $X worth". Have a comments section to note what type of driving: towing? highway? city? headwind/tailwind?

I started keeping a log of both mileage & service activity on my 1970 Continental in 1976 and have done so with each and every vehicle I have owned to this date. Every gallon, every mile. Such detail can also be a real plus for a buyer when you are ready to sell or trade.

dn.

 

15 MPG is about the max I have ever gotten.....1998 V8 mountaineer, stock tire size, 2wd, 74 mph. I was down around 13.5 for a while and could not figure out why. Thought gas quality was down, fuel filter, air filter, air intake leaks, or dirty intake/throttle body......so.....varied gas stations, replaced fuel filter, cleaned kn air filter, checked all intake connections, and cleaned intake/throttle body w/ sea foam.......... still 13.5 mpg.

Then, my cam position sensor started chirping....removed/replaced w/ new.......back to 15 mpg.

 

there is no excuse for 12 MPG with an unladen 4.6... or 14... a friend manages those same numbers with a V10 Excursion... if you have access to a scanner, look through ALL your sensor readings, particularly O2 sensors, they can stick and sometimes not trip a C.E. light... also, the rolling resistance may just be high in this model... some cars are just like that... I.E. the jeep liberty... but i have a lincoln Mark VIII, which weighs 4180lbs with me in the drivers seat, and i could get as high as 30 mpg on the highway, BUT the ABSOLUTE WORST i ever got was 13, and that was doing nothing but racing, burnouts, hitting the speed governor of 135 with five people in the car numerous times... even when towing a 3000 lb trailer in 3rd gear at 70 i could manage 18 to 22 mpg... maybe look into a tuner reflashing the ECM with a more fuel friendly tune? i'm not going to get into my theorys on why... i'll just leave it at "why would someone buy a 24 mpg Taurus AND a 15 mpg explorer, when they can buy a 22 mpg explorer?

 

Keeping a log of every gallon, every mile? Arn't you ever late for anything and don't have time for such nonsense?

 

Nope - at least not for that reason. This "nonsense" helps me identify potential problems before they become problems, know when to rotate tires, validate the benefit of upgrades/changes, etc. The key is to have a proper logbook in the vehicle and do your documentation when you fill up or perform your maintenance tasks.

Memories become fuzzy, but good recordkeeping endures - which helps your trucks do the same!

dn.

 

I also keep a log in each one of our vehicles. Every time we fill up the date, mileage,
gallons and oct. of fuel, and miles driven since last fillup. Makes gas mileage calculations
easy. Also list any and all service/repairs along with what was done and the cost.

 

Get about the same out of my Aviator, although it is the 4V motor, not the 3V. I do notice that with my other vehicle, when the weather is cold, the average MPG's are always lower. I guess it is just something you have to live with.

 

Third this notion. Also, are you filling up with pure gas or gas/ethanol mix? The ethanol has less energy, and makes the mileage look abysmal.

Winter takes its toll on mileage too. Long warmups, sticky trannys, more rolling resistance, etc. Don't be surprised if summertime gets you back up to 17 mpg.

 

If you have an android phone, an app called FUELGAUGE ( one word ) is a great app for logging mileage on all your vehicles. I've kept every fill up in my van until it died recently ( 141 fill ups ) it's a great app for those that want to keep tabs on their MPG.

Other than that, fuel mileage goes down with temperature as the coolant sensor will enrichen the fuel mixture much like the choke on a carburetor. Warmer vehicles run lean, colder vehicles run rich.

Also, a dirty MAF can cause mileage to plummet.

 

I see everyone commenting about making logs, recording miles, blah blah blah...

But does anyone have a REAL answer?

Ive done the fuel filter, air filter, tune up, and o2 sensors and no ethanol gas. Summer or winter its about the same.
My 04 4.0 explorer got 300+ ish per tank, this 05 4.6 gets less than my 80's 350.

No check engine light or anything.
Im getting 10mpg. The computer says i have roughly 300 mi till empty at every fill up, and I'm only getting 150 out of the tank.
I can manage 12-13 MPG if driving the the highway for the entire tank, no stops, gets me about 4 hrs of highway driving.

THE RECIPTS MATCH THE 10 MPG.
no mods, stock tires, new bearings, even tried removing the front driveshaft.

Any actual advice as to WHY im only getting 10mpg?

Edit: forgot to mention, 200k on the odo, and recent trans.
Could it be a worn timing chain? I have no noise or anything, engine runs amazing and smooth.

Never had a young v8 explorer to compare.

 

Do you happen to have an oiled performance air filter (such as a K&N or Sceptre)? If so, the oil from those filters can coat the Mass AirFlow (MAF) sensor and cause reduced fuel economy without any other obvious symptoms. Many auto parts stores sell MAF sensor cleaner that works pretty well and is probably a bit safer for nearby plastics than using brake cleaner.

Do you have a scan tool or other device capable of providing datastream information from the OBD-II system? If so, even though you seem to be opposed to logging, monitoring your short and long term fuel trims can offer some information.

-Rod

 

No, like i said, bone stock.

I did however try to monitor the Long-term fuel trim.
Bank 1 was around 7 and bank 2 sat around 3.
Unfortunately i don't know what that means in the long run.


(And Yes, I know I can abbreviate LFT it, but I feel like abbreviations in forums like this just make it extremely difficult for people who are new to the stuff to figure out what you're talking about, and people tend to abbreviate everything now adays out of laziness, which makes it even worse in my opinion)

 

So a long term fuel trim (LTFT) or 7 and 3 means that the computer is "trimming" the fuel injector pulse a bit longer (positive LTFT) because it thinks, based on various sensor readings, that the air fuel mixture is a bit on the lean side. So the positive trim number means the longer the fuel injectors on that bank will stay open, meaning more fuel is being injected into the cylinders. This can lead to slightly reduced fuel economy, especially if the sensor readings are a bit bogus for some reason and the increased fuel trim is not actually required.

So the next question would be what is causing the Powertrain Control Module (PCM) to think the air/fuel ratio is lean and increase the fuel trim? There are several sensors that enter into that equation such as the Mass Air Flow (MAF) sensor, the Intake Air Temperature (IAT) sensor, the Engine Coolant Temperature (ECT) sensor, up and down stream heated oxygen sensors (HO2S)/Heated Exhaust Gas Oxygen (HEGO) sensors, and I'm probably missing a couple.

Ford publishes an On-Board Diagnostics (OBD) System Operation Summary document by model year which explains what the PCM takes into consideration to adjust fuel trim, limits before a fault code is triggered, etc. It's not always the easiest to follow, and may require tools that non-professionals are likely to have, but may give you an idea which sensors to monitor to help determine if something is reporting unreasonable values.

-Rod