Gas Mileage DROPPED

[MXracer721]

I bought a 99 Explorer last June and when I first got I was getting around 300 miles to a tank of gas. For about the last 2 months or so my gas mileage has dropped quite a bit now I'm getting around 250 - 270 on a tank of gas. I never checked the exact mileage today. I always set the tripometer when I fill up and this last time was 270 miles with 20.9 gallons of gas which works out to just under 13mpg. At first I thought it was because I was warming it up, then we got snow so I was using 4x4 but this week all I did was drive. When I bought the vehicle the previous owner told me he had a problem with an intake gasket, which got bad gas mileage and he could smell fuel from inside the car. I'm not smelling any fuel but I'm not necessarily ruling that out. I've seen a few posts about "winter gas" but would it cause my mileage to drop that much? Oh I forgot to mention this a SOHC v6 with 69k. Is it time for new plugs and wires? New air filter? The previous owner was a retired guy and his wife drove it, and it was serviced at a dealer for everything and he actually gave me the service records for all the stuff that had been replaced, but I'll have to see if I can find them. Any help would be greatly appreciated!

 

[crashcookie01]

Is the check engine light on at all?

 

[MXracer721]

Is the check engine light on at all?

Nope not all. That's why I'm wondering what the problem is.

 

[crashcookie01]

The reason why i ask is because I had the same problem but my check engine light was on. So I just replaced the fuel filter and it seemed to do the trick. I have to see if my gas milage had changed cause I usually should have gotten 26 miles to a gallon when I was only getting 19 miles to a gallon.

I know that the fuel filter and o2 sensors will mess with your gas milage.

 

[Kinserin]

I've been having a similar problem with my 91... I used to average 400km a tank or 300km or so per 3/4 of a tank.. But now Im pushing 300 for a tank of 60L. Its sort of depressing. I first thought that maybe it was because I kind of forgot to check my K&N filter (Forgot to clean it for the longest time) so I cleaned it out, and did a few minor things but it still sorta sucks... I dont know what this 'winter gas' rumor is you mentioned but I hope thats all it is. 4 days for a tank of gas is killing me lol

 

[MXracer721]

The reason why i ask is because I had the same problem but my check engine light was on. So I just replaced the fuel filter and it seemed to do the trick. I have to see if my gas milage had changed cause I usually should have gotten 26 miles to a gallon when I was only getting 19 miles to a gallon.

I know that the fuel filter and o2 sensors will mess with your gas milage.

Wow I would love 19mpg. Would the o2 sensor set off the check engine light? How much are air filters? I may change that. May main concern is that it doesn't even have 70k miles and its only getting 13mpg. I have a trip to St. Louis coming up next weekend so I'll see how my mileage is with all highway miles. I need to get this figured out so if I have to spend money I get it out of the way before the motocross season starts up I'll have to pull a small trailer every time I ride and I don't even wanna know what my mileage will be like then.

 

[JDraper]

Moving to the correct forum...

 

[crashcookie01]

It may sound like a dumb question but is it all highway driving? As far as I know the check engine light does come on if the o2 sensors are bad. Air filters 10-25 dollars.

 

[MXracer721]

It may sound like a dumb question but is it all highway driving? As far as I know the check engine light does come on if the o2 sensors are bad. Air filters 10-25 dollars.

Mostly highway. I only drive it to work and back and today was mostly highway driving because I wanted to finish off the tank to see the gas mileage. It's definitely more highway than city. I could understand 15 or 16mpg but 13mpg on a v6? Somethings wrong. My p.o.s. dakota got better than 13mpg and it had 110k

 

[YOGIS Sport Trax]

bad gas?

I have a 2001 sport trac... 4" superlift and 32x11.50' stock 4.0l
getting 11-12.5 mpg..
anyone with some ideas out there... I can get a f-150 to do this bad...

 

[YOGIS Sport Trax]

ps.. new gas filter, maybe need o2's ?

 

[crashcookie01]

First do the routine mantainance change the air filter that type of thing. If your chaeck engine light is on try the fuel filter first cause that was what was wrong with mine. Then check the o2 sensors. Cost effective that way(cheaper to more expensive). Rules things out before jumping into a big expense.

 

[pumpkin]

I always set the tripometer when I fill up and this last time was 270 miles with 20.9 gallons of gas which works out to just under 13mpg.

You did the math wrong or is that really correct? If you pump that many gallons during fillup, you're running on fumes. That will clog the fuel filter in a hurry and it's bad for the fuel pump as well. Divide 270 by the number of gallons you put in to get the MPG.
I'd start with looking at the spark plugs to see what condition they are in.

 

[MXracer721]

Yea I did the math right. 270/21 = 12.8 I know I was surprised at how much gas I went through, the check gage light was on for maybe 10 miles. Today was the most gas I had ever put in the tank its usually around 18 or 19 at the most. How much is a fuel filter and how hard is it to change? I may just go with a new air filter, plugs and possibly a fuel filter. I'll pull the plugs out tomorrow and take a look at em, but I'll probably end up changing them. But how bad could they be, this thing only has 69k?

 

[crashcookie01]

The fuel filter will cost you between 10 and 15 dollars. And it is not that bad to change. As far as the spark plugs that is about the milage I changed mine. Your plan actually looks like a very good plan. But definately change the fuel filter if the check gage light came on.

 

[pumpkin]

Okay, I thought maybe it was a typo or something. The tank holds 20.8 and 1 gallon is probably enough to barely cover the bottom of the tank. I fillup somewhere between 1/4 & 1/2 tank.

Can't remember how much the fuel filter cost. I just moved and all my receipts are packed up in storage. I can tell you it was a P.I.T.A to get the filter off. I did it about a year ago. Some people here say it was easy but I had a hard time. http://www.explorerforum.com/forums/showthread.php?p=1428506#post1428506

Even though it has only 69K miles, it's 8 years old and maybe the spark plugs haven't been replaced yet.

 

[MXracer721]

Alright, so I bought a new air filter and fuel filter today. I'm going to put them on tomorrow because right now its 31 degrees out and raining/snowing/sleeting right now and I'd rather wait till I can use a lift. I'm not gonna be driving much this week but this weekend I'll be driving to St. Louis, MO from Peoria, IL and back so that'll be a good test to see if that fixes the problem. I checked one plug and it was a PITA to get out (not a big fan of working on cars, MX bikes are way easier) and it was a light brown color, if they were black I would have bought new but I really don't think the plugs looking the way they are would be the cause of 4mpg loss of gas mileage. The fuel filter thing sounds like the problem because there was a time this winter I completely ran out of gas at 243 miles (due to lots of warm ups because of weather). After that even w/o warm ups the mileage dropped. Hopefully the fuel filter is the problem and the air filter helps. Thanks for all your help guys I really appreciate it and I'll have a follow up after my trip this weekend.

 

[crashcookie01]

Good luck! Hope it works out for you

 

[kert0307]

I have a 2001 sport trac... 4" superlift and 32x11.50' stock 4.0l
getting 11-12.5 mpg..
anyone with some ideas out there... I can get a f-150 to do this bad...

Did you regear after getting larger tires? Find out what your gear ratio is. The code is on your drivers door, then look for the code on here. I suspect that having to high of a gear ratio is killing your mileage.

 

[89mclarenstang]

did replacing the filters help out your gas mileage?? just wondering because in the last 2 weeks here in ny my mileage has dropped as well...i usually get a little above 200 miles to the tank on my 96 v6 explorer and now im getting in the 170's and 180's... i dont really work on cars but if its easy enough maybe i can change these filters as well..anyone know of a place that has pictures and instructions on how to do it??