My wife drives a 99 expy with 5.4.The last two tanks it only got about 310 miles and used to get 350 plus as much as 375. Can it be because of winter additives. It's running great. No mods on it.

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1999 F-150 Lariat SC 2 WD, White/Silver, 5.4L, 3.55LS, K & N FIPK, Superchip, underdrive pulley set, Flowmaster dual chamber one in and duels out, six disc CD changer, towing package and captain chairs

 

Hi Mikey,

Yes, that could be a possible culprit, assuming as you said that it's running well, no check engine lights, and no recent changes or mods, no MAF or EGR problems. The use of what are sometimes called "winterized" fuel formulations, reformulations to combat poor air quality by oxygenating. This reduces raw energy content, and will lower gas mileage when compared to non-reformulated fuels.

Every year for the past 3 years now (a bit longer on some areas), this happens as we go into each winter, as the use of these reformulated fuels is phased in again, where the gas mileage drops, then it picks back up again in Spring in the areas that only require reformulated fuels in the Winter, some areas require it year-round. We see it here when people compare their gas mileage on non-reformulated fuels before installing the Superchip in summer or early Fall, to their results with the Superchip after reformulated fuels have been phased in, we've seen that for the past 3 years here on F-150 Online; and of course just about everyone sees this mileage drop at some point from Fall going into Winter, modified or stock, as it's a basic energy content issue, so everyone's mileage drops who is in an area using reformulated fuels. And that is of course the majority of the country.

Without knowing more, it's not possible to say positively beyond a shadow of a doubt that this is the sole reason why your mileage has dropped, but it's a very likely suspect this time of year all else being equal, meaning anytime from about mid-october to mid-December, as the use of reformulated fuels is phased in again each winter season.

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

[This message has been edited by Superchips_Distributor (edited 01-01-2001).]

 

All summer long, my Y2K had been getting around 13.5 (+-1) mpg. I got 14.5 on one 55-85 mph blast on a 350 mile round trip.

These past few tanks got as low as 10.5 mpg -- and/but that does include a lot of 4x4 in 5 (+-10) degree Michigan snow.

Over the years, I've always seen 10-15% reduction in mpg in winter -- regardless of vehicle.



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Y2K™ 7700 4x4
Jim - N8JG@Hotmail.com

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Hi Jim,

Since you've been observing this every winter for some time, do you have any feel for how much of this mileage drop each winter may be purely seasonal in nature, due to winter's colder temps & road conditions (4X4 usage, etc.), versus how much is from fuel formulation changes each winter?

I'm wondering if you have say, noticed that it starts at the same time on the calender each year (if you've tracked that precisely), given the fuel formulation changes of the past 3 years or so that is due to the Fed's air quality monitoring campaign?

It's minutia, most people will never track that kind of thing to that degree so it's a long-shot question of course, just curious if you have any insight on that angle in particular..........

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

 

Sorry, Mike.

I gave up keeping a log with the Y2K (but today's fill was 11.5 -- and it's been cold and the streets are 50/50 cleared/snowy in the 'Zoo. I've been using 4x4 approx. 40% the past two weeks).

I have no facts to support it, but believe that the switch-over to 'winterized' fuel here is mid November -- and that seems to correspond as much to earlier year switch-over as it does to the start of snow/cold.

Having some experience with statistical methods (and a recent re-introduction to MiniTab) -- I know that my 'process is not in control' -- meaning: I have neither sufficient data nor accurate-enough measurement discrimination to render a factual opinion -- other than that I know that my gas mileage now sucks -- and it is mediocre in the summer.

Anything else would be woefully subjective.

Happy New Year!



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Y2K™ 7700 4x4
Jim - N8JG@Hotmail.com

Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"

 

Doh!

[stttttuttttered on the key-punch]

[This message has been edited by jgorka (edited 01-06-2001).]

 

Hi Jim,

OK, I knew it was a terrible long-shot before I asked, thanks for the info you wre able to provide.

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

 

Jim and Mike;
I drove to Michigan over the Christmas/NYE Holiday. I was getting about 15 around town in Richmond. I drive all of those highway miles at my normal speeds (about 10 over the speed limit) and I averaged barely 14.5. I got almost 18 on a similar trip in late summer. The tires were new and filled with air, and very little or no 4wd. Today I removed my superchip and I am going to reset the computer. I thought I might give the computer a chance to relearn. Mike, I've been using Texaco premium when I can get it or Amoco ultimate. (I really liked the 18 mpg numbers!) I didn't notice a drop last winter, but I was also living in an area where they use oxygenated gas year round... THanks for any help.

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'99 F150 SC Lariat 4x4 Deep Wedgewood Blue w/Harvest Gold 2-Tone, Medium Prairie Tan Leather, most of the factory options, Polar Bear Brush Guard, 2 165W KC Daylighters, Ford Factory Steb Bars, Extang Tonnuea Cover, Duracoat Liner with Rubber Mat, Flowmaster 50 series, Superchip, K&N Filter, Airbox Mod and Silencer Removed, 2 Rockford Fosgate 8"'s and a 250 watts RF amp

 

12.8 MPG tonight. I live in a rural setting and speeds this past tank were up to 55 to/from work and shopping with little or no 4x4. Previous tank was 10.5 with heavy 4x4 in the snow.