Expedition Mileage Drop

[lncoop]

Here be the deets: 2005 Expedition 4x4 with 85k miles. Great truck that's given me no real problems other than a cracked throttle body, which is pretty well a given on those (thanks Ford), but something strange is going on. Last week I towed the party barge up to Table Rock Lake. I expected to get bad gas mileage, and I did; twelve and change. No surprise there as I was towing a big load in the Ozarks. However, now that I've been back for a week I'm still getting twelve and change as opposed the usual fifteen and change. Anyone have any idea what might be causing that?

 

[foodfisher]

Re: Expedition Mileage Drop

Got a check engine light? My mileage drop,Dodge Hemi, was due to a bad 02 sensor.

 

[drrpm]

Re: Expedition Mileage Drop

An O2 sensor on the way out can do that even before the CEL comes on.

 

[lncoop]

Re: Expedition Mileage Drop

Gotcha. No CEL.

 

[12vMan]

Re: Expedition Mileage Drop

15+ mpg sounds pretty good to me for a 4x4. I have an '04 2wd that gets the same. I have over 120k and replaced the o2 sensor about 10k ago when it started running a little crappy, before the CEL came on. Your issue seems to be a sudden thing, not like plugs, although you are getting close to replacement time on those.

 

[robert graham]

Re: Expedition Mileage Drop

Maybe the hot weather(high intake temps) causing reduction in mileage? Clean air filter?

 

[GA_Boater]

Re: Expedition Mileage Drop

You said no CEL, does it light at start-up? The bulb could be burned out. Easy to miss with all the lights on the dash on cars today for seat belts, air bag, CEL, etc. - Looks like Christmas.

An OBD II code reader won't give codes if you don't have a CEL. But, speaking for my reader, it does have a real-time monitor option that displays sensor outputs and the normal sensor range. Something to look at. Maybe a sensor is on the way out but not quite into failure mode.

Hope you get those 3 MPG back, gas is too dang expensive.

 

[bruceb58]

Re: Expedition Mileage Drop

Clean air filter?

For a fuel injected car, air cleaner makes 0 difference for MPG.

 

[lncoop]

Re: Expedition Mileage Drop

Thanks for the ideas fellas. I talked to two of the Ford guys here (several dealerships in the area) and they both said it probably just needed time to moderate after all that extreme towing. The second one I talked to told me to give it a couple thousand miles. Makes sense because I really don't drive that much during the week. I just filled up this morning for the first time since the trip. They did both say I should go ahead and change the plugs even though the original recommendation was 100k miles. I assume that's in hopes of avoiding the dreaded broken plug syndrome that has swept through Forddom like a plague. Dagummit Ford! Oh well. Still love my Expy.

 

[Jlawsen]

Re: Expedition Mileage Drop

Are you manually checking the mileage or taking it from the dash display. If its the later, the mileage will be the average of all the miles you've driven since it was last reset to 0. Depending on the miles since the last reset it could be 1000 miles or more before you see it come back to normal. The bad news is that you're towing mileage was a lot worse than you think. My F350 6.4L gets 6 +/- when I'm pulling the 40 footer. I get about 12 tops freeway when I'm pulling the 16 footer and average 10-11 around town. However, it's lifted 8" with 35's and weighs 8,000 lbs so when it comes to rolling resistance and aerodynamics, I'm right there in the cynder block class.

 

[rogerwa]

Re: Expedition Mileage Drop

Do the plugs. It may be a pain but it could get way worse if you leave them.. That passenger side rear plug is a real test of your manhood.

 

[dolluper]

Re: Expedition Mileage Drop

Did you forget to take it out of tow mode......most code readers will give you pending codes also....after three bad passes your light will come on