wth! my van's MPG went from 23 to 8.

[waggy]

ok as the title says my MPG on my windstar went from 23 (country driving) to 8 (again country driving).

sigh guess i should take it in. bah.

 

[LTC8K6]

Strange to get that bad without the light coming on.

 

[JeffreyLebowski]

Fuel pump, spark plugs, air filter, fuel leak?

With that dramatic of a drop the vehicle should be running like crap. If it is running as it always has, I'd suspect a fuel leak somewhere.

 

[cprince]

Fuel pump, spark plugs, air filter, fuel leak?

With that dramatic of a drop the vehicle should be running like crap. If it is running as it always has, I'd suspect a fuel leak somewhere.

that and also the brakes and wheel bearings. Make sure all wheels spin freely.

 

[CurseTheSky]

If there's no obvious noise, hesitation, or warning lights, my best guess for such a dramatic decrease is a puncture in the gas tank or fuel lines.

 

[exdeath]

Hook up a scanner and check long term fuel trims, I ll bet they are maxed out on the + side and there will be a pending code for system too lean that hasn't lit up yet. Also no light could just mean a burned out MIL lamp, always check anyway.

Low transmission fluid and malfunctioning torque converter can also have a huge impact on mileage.

 

[Nyati13]

I had a timing belt failure one time where it didn't break, but it allowed to timing to change (and continually get worse). The car got very sluggish, and was wasting gas like crazy.

 

[Greenman]

Release the parking brake.

 

[SSSnail]

How old? O2 sensor?

 

[Bignate603]

Hook up a scanner and check long term fuel trims, I ll bet they are maxed out on the + side and there will be a pending code for system too lean that hasn't lit up yet. Also no light could just mean a burned out MIL lamp, always check anyway.

Low transmission fluid and malfunctioning torque converter can also have a huge impact on mileage.

What would cause that? Dead/dying O2 sensor?

 

[Demon-Xanth]

Usually major drops like that are caused by something like the MAF or O2.

 

[punjabiplaya]

old Sentra did that once. problem was a leaking/busted fuel pump

 

[DougoMan]

If you are lucky it is the oxygen sensor.

 

[jaydee]

Sounds like someone siphoned your fuel tank, or you've got a leak somewhere (or the parking brake is on, lol). Bad sensors wouldn't bring it down 66%, and if it did, you'd have a CEL light and it would be running like absolute crap.

 

[LTC8K6]

Maybe he put E85 in it...that'll kill your fuel economy by 25-30%

 

[bunker]

Had the same thing happen to a '91 Ranger I had. O2 sensor was the cause.

 

[potato28]

Check the intake runner control module.

 

[Howard]

Maybe he put E85 in it...that'll kill your fuel economy by 25-30%

No way in hell. Even if the ethanol had zero energy content, the decrease in fuel economy would be 15%, unless you're saying the ethanol has a negative effect on the overall system...?

 

[Bignate603]

No way in hell. Even if the ethanol had zero energy content, the decrease in fuel economy would be 15%, unless you're saying the ethanol has a negative effect on the overall system...?

You might want to check your math there... E85 is 85% ethanol.

Ethanol has about 75700 btu/gal
Gasoline has about 115000 btu/gal

If you do a weighted average for an 85% ethanol/15% gasoline mix you end up with 81,595 btu/gal, a 29% drop in energy content/gallon.

 

[LTC8K6]

No way in hell. Even if the ethanol had zero energy content, the decrease in fuel economy would be 15%, unless you're saying the ethanol has a negative effect on the overall system...?

http://www.caranddriver.com/var/ezf...lication/04b8987d7b1d3ed794ea9a354dc9b755.pdf

From a 2011 Owner's manual:

Starting
The characteristics of E85 fuel make it unsuitable for use
when ambient temperatures fall below 0°F (-18°C). In the
range of 0°F (-18°C) to 32°F (0°C), you may experience an
increase in the time it takes for your engine to start, and
a deterioration in driveability (sags and/or hesitations)
until the engine is fully warmed up.

NOTE: Use of the engine block heater (if equipped) is
beneficial for E85 startability when the ambient temperature
is less than 32°F (0°C).

Cruising Range
Because E85 fuel contains less energy per gallon/liter
than gasoline, you will experience an increase in fuel
consumption. You can expect your miles per gallon
(mpg)/miles per liter and your driving range to decrease
by about 30%, compared to gasoline operation.

 

[Howard]

My mistake, thought the "85" referred to the fraction of gasoline in it.

 

[KK]

ok as the title says my MPG on my windstar went from 23 (country driving) to 8 (again country driving).

sigh guess i should take it in. bah.

my 2001 windstar is only getting us around 18 mpg now. used to get around 21-22 but I guess after 170k tolerances might not be as tight.

My 1994 ranger once got pretty bad gas mileage, but I think it was because the thermostat was running wide open all the time and never warming up the engine.

 

[waggy]

i checked the lines and no puncture in the tank.

bah guess i take it in. a few other people i talk to say the 02 sensor. hope its not expensive or hard to fix.

on a side not i forgot i even posted this. i was about to post this asking if it could be the 02 and how to fix it..sigh im getting old.

 

[hanoverphist]

How old? O2 sensor?

this is what i was going to post... i had the downstream one go out on my truck and my mileage went from 17 to 7.5mpg. easy fix too.

 

[waggy]

from what i been looking at the o2 sensor is a easy fix. just a matter of getting the right one.

i shall attempt it! ..if my van blows up ..well i love you guys!