I was getting 12mpg stock. When I upgraded to flowmaster, airaid, superchip and headers I went to 13.5mpg. With the addition of the Supercharger I gained 2mpg up to 15.5mpg!When towing I've been getting 9mpg regardless of trailer weight.
For now I'm running the stock 245's.

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2000 XLT supercab, 4x4 7700lb. package, 5.4L, 3.73 LS,skids,CD changer,MagnaCharger, Flowmaster,Superchip, Airaid, Gibson Headers, Island Blue

 

The only mod was:

Adding 20' Wilderness Trailer

150 miles highway

Fill tank to overflow both fills

75 miles @ 60 MPH

40 miles @ 65 MPH

20 miles @ 70 MPH

15 miles @ 55 MPH

Ran in Overdrive (with too many converter-unlocks and downshifts to suit me) over I-94 and I-69 (grades are not more than 4%?? over Michiana flats).

10.2 MPG -- Not bad -- wonder what it will do in Direct-only.

Oops! Forgot to post weight: 11K +- 200

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Y2K™ Jim

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"



[This message has been edited by Y2K 7700 4x4 (edited 08-20-2000).]

 

14 city, 17 highway before and after the mods. Really poor mileage when new; hope to increase a little with more mileage.

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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
Class III tow/Payload #3/Convenience pkgs.,
4-wheel disc/ABS,Chestnut/Parchment 40/60,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification, Superchip,
Dynomax ultra-flow welded 3" cat-back,
3" exit Y-pipe, Hellwig rear anti-sway bar.

 

Ok, I've now got the exhaust and the WMS intake on, and took a little roadtrip this weekend. 211.7 miles on the odo and I filled up to 12.927 gallons. That's 16.38mpg. I had reset the computer after the installs and drove around town a couple of days before this weekend so this is a fair measure after the computer has gotten used to the mods. Most of the driving was about 73mph on the interstate, but about 40 miles were on two lane highways where I had to do some passing.

I have the off road package with stock 17"ers and 3.55 gears. See my sig for the rest of the info. My truck only has about 4800 miles on it too, so hopefully mileage will keep increasing with age

Sven

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2000 F150 XLT 4X4 Off Road 5.4L Reg. Cab
K&N, WMS Velocity Tube, and Gibson Sweptside...

(For now)