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Keith Lawson 2

Keith Lawson 2

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New member here, sorry if this has been asked before, but I couldn't find it.



I have a 2004 Sport Trac XLT with the 4.0L-6, automatic.4x4, bone stock, no mods.



When I got it in 2006, used from the service manager of the dealer, with 15k miles on it, I checked it the first weekend and it got 21 on the highway. It got 20 or so and averaged 17/18 most of the time for a couple years, all around driving. I didn't buy it for the MPG, but...



Over the years, even with care (and I am anal about that) the MPG has dropped. And dropped. Now it sees about 14/15 highway, and you don't want to know what it does with E85 or with it in 4x4 in winter! Still, summer, highway, and 15? I've also tried different brands of gas. No help.



The shop and I are at wits end on this issue. New plugs, you name it, no codes, even a new fuel line, no leaks...



Anyone have any ideas?
 
Have you changed tires since then from OEM to some other brand. Tires can make a difference when it comes to Rolling Resistance and the compounds they're constructed with.



The other thing would be a slightly greater drag in your calipers since they were new. It's possible that even the materials of a different pad manufacturer could cause a difference in drag.



I'm sure there are other driveline variables that could affect gas mileage but I would think the tires are the first in line for something like loss of mpg.
 
Tires and age.



Valves, valve guides, cams, rings, seals, friction, tolerances, and the additional "pedal" required to compensate, all affect efficiency.
 
Keith,

I doubt that there is anything wrong with your Sport Trac that you cannot fix yourself.



First is Tires. If you changed tires and changed tire size, that may be the source of your MPG differance. You may be getting speedometer error and you are no longer getting an accurate Speedometer/Odometer reading because of the change in tire size. Also, make sure your tires are inclated properly and even up to 4-5 PSI above the normal inflation pressures.



Second: Possible error creeping into your MPG calculations. The most accurate way to dermine MPG is to fill up the tank to the brim...I fill up until I can see gas above the restrictor door in the fuel filler neck. Then I drive at least 50 miles, but the more miles, the better and more accuate your calculation will be. Then fill up at the same gas pump, and again fill up until you see gas in at the restrictor door in the fuel filler neck. Write down the gas pumped down to the 100ths or 1000ths of a gallon. DO NOT round up or down. Also jot down the miles driven including the 10ths of a mile...again do not round up or down.



Third: Traffic. Evaluate your normal driving. Are you taking a different route to work, etc. Is the traffic heavier than it was before. School zones tend to increase mileage when school is in session. Are there new traffic lights, or have the lights changed their timing causing you to stop at a light longer than you did in the past?



Forth: Check your driving habits. Are you accelerating more quickly? Are you driving faster and more agressively? is there more inclement weather or is it colder now? Not much you can do about the weather, but your driving habits have a major impact on your MPG.



...Rich



 
@Richard L



I've read discussions about causing possible damage to your Evap system if your overfill right to the top of the filler tube. Might not be a good practice to suggest. Filling it a the same exact pump and let it fill to the automatic shut-off point would probably be very close and not affect an average mpg calculation.



I believe driving 200-300 miles would serve better to get an overall mpg average under all types of driving conditions and to chart averages over a few months - then average those results to factor out different modes of travel.
 
On my trips back to my old home town in PA I used to buy gas at the only station in town because they were actually one of the lowest price stations in the entire area. I don't know how many times I tried to explain the damage they could be doing to their customers' vehicles by overfilling their tanks but the teenage kids pumping gas there just refuse to stop at anything less than an exact dollar amount. I guess they can't do math either. The only time I buy gas there now is if I need a little for a lawn mower or ATV. My ST has to pass an emissions test every two years in Ohio and one of the checks is the evaporative emissions system. I just went through the test yesterday morning and fortunately it passed.
 
I have always gotten anywhere from 15-17 mpg since bought in 09 (02 4x4) I always thought I should be getting slightly better. My tires, which need to be replaced also, are smaller than stock 245 vs 255 (were new when I bought truck). My brakes are bad and im sure driving habits have all something to do with it for me
 
Fill it up until the pump shuts off. Stop there, record your odometer. This is your full tank base line. Now for the next month (or so) write down or somehow record every drop of gas you put into that ST. At the end of thirty days (or so) fill the tank until the pump shuts off. Now add all the fuel you used since, but not including the initial fill (tank base line). Next subtract your odometer reading (you recorded this) at the base line fill up and from the odometer reading at the end of the test. Now divide the mile by gallons. This method will give you a thirty or so day average. One tank is not a valued measurement. In one tank there can be one incident that will skew the whole deal.

By using more than one tank your AVERAGE MPG will be more accurate of your vehicle and driving habits. Again do more than one tank to get a good average.

My 2001 in mostly urban driving gets around 17 (summer and winter in Iowa). Pulling a utility trailer around 1,000 pounds from Iowa to New Mexico I usually get 15 and we don't go slow.

Hope this helps.

Dennis

.
 
toptobottom,



I don't recommend filling to the brim on every fill up, but for an occasional mileage check, its the only way to get an accurate reading.



I have done mileage checks this way on all my vehicles and have never had an issue with occasional overfilling, and no Evap Caister problems.



Part of the Evap system is a fuel/vapor separator, which sends fuel vapors to the canister and liquid fuel back to the gas tank.



Yes, the fuel/vapor separator can be overwhelmed if you constantly over fill your tank and send some fuel to the vapor canister. Too much fuel in the vapor canister can ruin the canister, but an occasional overfill will not cause damage.



As for using the pump auto shut off, they don't all work the same, and even the same pump's auto shut off can vary significantly based on the temperature and the amount of vapors in the fuel tank.



...Rich



 
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It seems that it does not matter how visually full is the tank because all methods rely on the gas pump meter and vehicle odometer. For the purpose of determining fuel mileage at the accuracy of these measuring devices and other variables (vehicle, pump and temperature) - eight "half tanks" is as accurate as four full tanks; certainly accurate enough.
 
+1 what Yardsale says.



Don't stress out how full you fill the tank every time. Just fill it up, record the mileage, and from that time forward record every bit of gas you put in it, even if it is just $5 worth. Then, after 6-8 tanks, check divide the total amount of gas that you put in it by the total miles driven. The more tanks of gas and mileage you use, the more accurate the average MPG will be.



None of my Tracs have ever gotten more than an average of 18 MPG on the highway for long trips, and my average for all miles driven in town and on highway is around 13 MPG.



If you want great gas mileage, you should have gotten a Prius. Maybe a 4-cylinder base model Tacoma might do a little better. These Tracs are HEAVY vehicles with poor aerodynamics, and it takes some fuel to push them down the road.
 
Yardsale,

Yes, it really does matter. When you refill after your mileage test, you need replace the same amount of gas you used to get an accurate reading. The only way to know exactly how much gasoline you used, you must fill the tank to same level it was before you started your mileage test. Since this is a gas mileage test over a very short distance..50-100 miles, you have to be accurate since a 10th of a gallon or a 10th of a mile error can make for huge inaccuracies in you mileage calculations.



You cannot use the fuel gauge to calculate gas mileage and you cannot rely on the pump shutting off at exactly the same gas level.



Yes, you can use the Odometer and gas pump readings to get a reasonably accurate gas mileage but you need to drive for at least 1000 miles or 4 tanks full of gas....then the readings will normalize any small errors. When you are only making a short mileage test of 100 miles or less, every small error will create significant inaccuracies.



That's why I often question some people's gas mileage calculation methods when the drive 20-40 miles in traffic back and forth to work and then claim they are getting 25+ MPG in a Sport Trac ??? They may believe it, but I don't.



...Rich



 
Yardsale,

Yes, it really does matter. When you refill after your mileage test, you need replace the same amount of gas you used to get an accurate reading. The only way to know exactly how much gasoline you used, you must fill the tank to same level it was before you started your mileage test. Since this is a gas mileage test over a very short distance..50-100 miles, you have to be accurate since a 10th of a gallon or a 10th of a mile error can make for huge inaccuracies in you mileage calculations.



You cannot use the fuel gauge to calculate gas mileage and you cannot rely on the pump shutting off at exactly the same gas level.



Yes, you can use the Odometer and gas pump readings to get a reasonably accurate gas mileage but you need to drive for at least 1000 miles or 4 tanks full of gas....then the readings will normalize any small errors. When you are only making a short mileage test of 100 miles or less, every small error will create significant inaccuracies.



That's why I often question some people's gas mileage calculation methods when the drive 20-40 miles in traffic back and forth to work and then claim they are getting 25+ MPG in a Sport Trac ??? They may believe it, but I don't....especially when they quote the amount of gas they used as 1/4 tank full, etc meaning they are using their gas gauge to calculate gallons of gas used...:banghead:



...Rich



 
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Keith



Do you live in an area that uses 10% ethanol? When I lived in Kansas and Missouri, I would get hammered on mileage when they went to the full 10% as opposed to less than that depending on the season.



I used to use K&N Air filters religiously, but although the truck breathed better, it used more fuel to compensate for the additional air.



I use an Android app called Fuel Friend Lite to track mileage. It's no more exact than any other method, but it takes the human factor out of the calculations. it also accounts for partial fill-ups.
 
"especially when they quote the amount of gas they used as 1/4 tank full,"





My '02 will get 100 miles on the top 1/4 tank, and currently has 175 miles on about 1/2 tank, but it won't go that far on the bottom 1/2 tank. Point being my gas gauge is not consistent in it's degree of accuracy throughout the range. My '01 is pretty consistent, though. I had a '68 F-250 years ago that I drove 50 miles after it hit empty. (Dad didn't get 2 miles in it the next day, and yeah, I heard about it!!) On the other hand, I almost ran out of gas in his '70 F-250 with 1/8 of a tank showing on the gauge. Gauges cannot be trusted.



 
Thanks for the tips. :)



I've done most everything listed; on 3rd set of tires, thanks. Factory spec size according to inner door sticker. I'm not a moddy person, you see.



Sometimes I get wild and have a magnet or a sticker.



Heck, Mom's old 77 Lincoln did better than this...



For the questions I remember: We have 10% ethanol here. No pure gas. You can also get 30% and E85. Let's not go there!



My tires were the factory Goodyear-something when I got it. At about 50k they began to make a flapping noise, even with good tread left. I have Mesa AP/2 now, made by Cooper I think. I hate Goodyears.



As for the Prius comment, I hit one once. Bent my bumper. Pissed me off.

The Prius fell apart totally.



I didn't buy the truck for MPG, but the drop over time had me worried.



Thank you all for the replies.
 
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Yardsale,

Fuel level is not used in the calculation...You refill the tank to the exact same level that you started with, and then use the gallons on the pump reading to calculate mileage.





If you just rely on the gas pump shutting off, it may not shut off when the tank is refilled to the exact same level as you started with, and the pump only shows the amount of gas pumped into the tank, but that may not be exactly the amount of gas you used during the test.



Since you cannot see the gas level in the tank, the only indicator that you put in the same amount of fuel in the tank that you used is to refill it until you can see the gas at the restricter plate in the filler pipe.



Again, this is only for a very short but accurate mileage test that you may only do once or twice a year. The +/- margin of error in the typical MPG calculation that simply uses the pump reading and Odometer readings eventually balance out the more miles you drive and the more you times you fill the tank. A 10th of gallon error over 15000 miles is insignificant, but that same 10th of a gallon error in a 15 mile test is a very significant error.



"Small errors in a small sample size, create larger errors."



...Rich
 
Richard, my point is that a 100 mile MPG test is worthless. Too much variables that you cannot control. The best way to get an accurate MPG is to do the calculation with several TANKS of gas over a thousand or more miles.



The pump automatic shutoff is not a calibrated consistent measure. All it takes is a little splash back when filling and it shuts off the pump. Is your tank really full to the same level it was at the last fill up? No body knows.
 

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