Poor Gas Mileage

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07navi

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There was a guy posting a while back about that. His claim was that O2 sensors are an item that should be periodically replaced, even with no codes. Sort of like replacing plugs. I think I saw another post about how you can get the data the O2 sensors are providing and make a decision about how "healthy" they are. The guy claimed it can be a big hit to MPG. Pretty expensive to replace I think so it seemed like money chasing money. I've been curious about that since I saw it.
They will go a long time and not bad to replace yourself. My Excursion ones are over 200k miles and doing fine.
 

07navi

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So I just bought a 2009 EL a few weeks ago. Previous owner did not clear the onboard computer and it read 9.2 MPG average. I figured he must have towed a trailer or something. Long story short, best I could do was 11 - 12 MPG, city/hwy. Put new plugs in it last week even though it was running smooth. Now getting 20.4 on the HWY (60 MPH on Cruise Control for approximately 100 miles) and 14.9 city. And for the non-believers, here is the screenshot to prove it. Loving life in the new Expy now.

qaSVPjs3_XAsR8AsaCnQ3SBBtz_6cS-_9_Ww2fSHLhYTF5vKiqCy-DlivLNdYTPkpbophGJaE1qbrb0LDS6EaTDCH5J4pSgrwyRDZNl1Des0Lqotvto507WDWo7ebi4E-BHkzmOHWNBTbBtYXSqcg3irO8Bu93ypQR_zI3QPUZJElpsWqx_1hyFMVUy9F3b72Z9z8kuXSwzY1T9hk_O0nEJ6qTLHMxiqNjwfJLiXh1dhxFNxrppYMG3TDdEwTAHIlbZAzpND5FJss0OH7wl__3gPUIXhuKiMBLlJMvj4vKrplIH7VNFni-AGK2lJ8pp70pUwTh0oDcwJmaV4nBZa9a_KQ0vr_PhVlqPUQh8I4SANr5fAlG6ahld1VOS8rIAzJghDCMdDe8k55dT5ns0O_jB41W1aWujnR9CwrMuxMPzixarstszeHJQttUGAmbN2hSHPjvsjYouCPusg53OCqzkor6pxvbH1LVTTctJD9OVshSQpVmtWQkhVfqpf-mX5iG5UX2Uks81-K0OnwTMXXa9gt7gc46eFgzGFb2uyphBRaaI6NMkysy6CKgbEJpH11soQ9gzncixb9u4bI8B0A9eQ__1AibSvgvHnHFEJCVac7yzyBYdRBQ0LelxSa49wsjoEZxRL2pidRrSmoHximY1Xe1SbRo37YgqIHVFHcQnAxNw656cy4jE=w937-h703-no
But how accurate are those info box read-outs?
 

762mm

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When I was a member of the Explorer forums, some guys would "refresh" their O2 sensors by removing the sensor and burning the carbon and other deposits off with a torch. Apparently these sensors are plenty strong to take the heat.

My 2014 struggles to get anything over 13 MPG city/highway (mostly highway). This is with new plugs, new air filter, MAF clean, throttle body removal + complete clean, new serpentine belt and idler pulleys, new water pump, new coolant, synthetic motor oil and all new fluids in diffs, tranny + transfer case. Fuel economy is still garbage, even though I drive it conservatively.

I might actually try putting in new O2 sensors in it this summer to see if it helps. I've read that the injectors on these might also cause piss poor fuel economy as they age, even though they still work. It also has a passenger-side phaser tick when warm and I've read that fuel economy issues can be caused by timing issues as well, which the 5.4L 3v is famous for.


So, all in all, it could be a hundred different things, all of which will cost you and are a crapshoot. Isn't all this new "fuel saving technology" just awesome, lol?


:rolleyes:
 
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tommyddsr

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Not sure how accurate they are but comparing before and after using the same on board computer shows a significant improvement regardless of how it stacks up to good ole manual calculation. So I'm happy.
 

rwmorrisonjr

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Make sure you do you calculations using summer blend gas (or ethanol free if you can find it). Winter blends always use more oxygenates which degrade gas mileage. E-10 (most common blend) decreases mileage around 5-10%, even in summer blends.

I noticed that when I moved from DC to Memphis, my mileage went down even though traffic isn't as bad and I wasn't commuting as much. I spend more time doing short trips (under 10 miles) in city traffic instead of 45-50 mile commutes on the Beltway at highway speeds which boosted my mileage numbers on the computer. I'm still using less gas, but my DTE and MPG numbers from the computer suck.
 

Herby

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Stop looking at the on board computer display. Then start driving it like a heavy tank. Nice and slow, my 07 get 22 to 24mpg highway, city I never checked. As I rarely drive in any cities or towns
Your 07 gets between 22 to 24 mpg on the HWY?!?! Great numbers. My 07 has reached 19.5 mpg max on the HWY. Changed fuel filter, plugs, air filter and cleaned mass air sensor to increase numbers but no good. Next move is to have my fuel system cleaned along with injectors. Hopefully I will see improvement.
 

Logan97

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It's funny that my passenger side front o2 sensor is throwing a code and I'm actually getting 1.5 more mpg.
 

Logan97

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Your 07 gets between 22 to 24 mpg on the HWY?!?! Great numbers. My 07 has reached 19.5 mpg max on the HWY. Changed fuel filter, plugs, air filter and cleaned mass air sensor to increase numbers but no good. Next move is to have my fuel system cleaned along with injectors. Hopefully I will see improvement.
I did all that on my 07 too and got the system cleaned out and I've only ever gotten 18 on highways
 

injunear

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My 13 Ltd Max has a fresh motor only gets about 14 mpg getting Po34 code changed o 2 sensors, cat cleaner, air filter, next is replacing cats. Org. motor had 125,000 miles. About 10,000 on new motor, so the cats have 140,000,life expectancy of cats are around 10 years.Hope this helps
 

plumcolr

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Check for dragging brake, or possibly front wheels not disengaging from axles while in 2wd. If you have a heat sensor, check rotor temp on all 4 wheels after a short drive. They will all be warm, should not be hot. You could use your finger, but wet it first as a dragging brake can be very hot. For IWE not working (if 4wd), take a short drive in 2wd. Do not turn off engine, jack 1 front wheel at a time and turn. they should turn easily with little drag. If stiff, see if axle shaft is also turning, which means IWE is not disengaging.

If you drive in 4a, turn it to 2wd and see if there is a difference.
 
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