7.3 poor fuel economy

300Merc · 04-02-2010, 11:01 PM

so i bought a 99 f250 7.3 recently, and i noticed that i have been only getting 11 or 12 mpg on the highway... the truck is bone stock. so im wondering what could it be? I know that i should change the fuel filter but ive been at school and ive been busy. im off tomorrow and ill probably get one then.. i have those bfg all terrain tires that are pretty far worn and i figured that could also be the problem since they are wide and create alot of rolling resistance. what about an intake or exhaust?

**plainredtruck** · 04-03-2010, 02:25 AM

Your tires could cause issues, but a new fuel filter probably won't hurt.

Neither will an intake or exhaust system.

Or an economy tune.

And a light foot.

I get 20.9 mpg avg with mine all-told (calendar year 2009 and holding steady for 2010) with those simple changes + a bed cover and biodiesel (no more than B20 - mostly B5 these days).

Is yours a 4wd? If so, check the hubs to make certain they aren't locked and check your brakes to make certain they aren't dragging.

prt

Zaairman · 04-06-2010, 02:09 AM

Something isn't right... or you're doing 90 MPH on the highway and driving like a banshee. How are you calculating the mileage?

driximus · 04-07-2010, 03:50 PM

make sure your tire pressure is right also. I had some pretty low milage a few tanks ago couldnt figure out why then I decided to check my hubs and I had them Locked from one of the few times I used my 4x4 lol.

300Merc · 04-14-2010, 03:13 AM

im usually cruising at around 65 mph and im pretty easy on the throttle

jermort · 04-16-2010, 04:20 PM

My truck has never, never got above 18.5 mpg. In defense, I do live at 6,500 feet and there is a 1,000 ft. drop in altitude between me and work.
Winter diesel blends usually drop my mileage about 2 mpg.
That said, I have been religious about tracking my fuel for the past 2 years and currently see 15.2 mpg average for that time. This includes winter, summer towing of my 7.5 k lb tt and 80 to 90 mph trips to Ill.

Yeah, I'd love to see 20 +. Realistically, 16 summer, 14 winter, 13.5 towing. Don't think my #s are too far from the norm.

jer

van_350sd · 04-17-2010, 09:09 AM

You don't have one of those Gray CMP/CPS Units do you?

Zaairman · 04-17-2010, 02:38 PM

Quote:

Originally Posted by 300Merc

im usually cruising at around 65 mph and im pretty easy on the throttle

How are you calculating fuel mileage? Do you fill the truck up ALL the way til you can see standing fuel in your filler neck?

Quote:

Originally Posted by van_350sd

You don't have one of those Gray CMP/CPS Units do you?

I do in mine. Last tank was just shy of 17 MPG. Lots of back road driving here in the Ozarks...which means lots of big hills.

04-02-2010, 11:01 PM	#1
300Merc Junior Member Join Date: Feb 2010 Posts: 7 Points: 1,028 Thanks: 3 Thanked 0 Times in 0 Posts	7.3 poor fuel economy so i bought a 99 f250 7.3 recently, and i noticed that i have been only getting 11 or 12 mpg on the highway... the truck is bone stock. so im wondering what could it be? I know that i should change the fuel filter but ive been at school and ive been busy. im off tomorrow and ill probably get one then.. i have those bfg all terrain tires that are pretty far worn and i figured that could also be the problem since they are wide and create alot of rolling resistance. what about an intake or exhaust? __________________ Early '99 ford f-250 Powerstroke DP Tuner, Isspro Guages Pyro, Boost, Trans Temp MBRP 4" exhaust Exhaust Brake Mod, TC Lockup switch, 315 75 R16 tires, leveling kit 1983 Mercedes Benz 300D

04-03-2010, 02:25 AM	#2
plainredtruck Senior Member Join Date: Dec 2008 Location: Hickory Tavern, SC Posts: 4,090 Points: 26,680 Thanks: 275 Thanked 444 Times in 285 Posts Images: 11	Your tires could cause issues, but a new fuel filter probably won't hurt. Neither will an intake or exhaust system. Or an economy tune. And a light foot. I get 20.9 mpg avg with mine all-told (calendar year 2009 and holding steady for 2010) with those simple changes + a bed cover and biodiesel (no more than B20 - mostly B5 these days). Is yours a 4wd? If so, check the hubs to make certain they aren't locked and check your brakes to make certain they aren't dragging. prt __________________ '99 F250 X-cab 2wd powered by DP-Tuner My Photography addiction Mafia # 27

04-06-2010, 02:09 AM	#3
Zaairman Mod Friendly Title Join Date: Dec 2008 Location: St. Charles/Rolla, MO Posts: 2,697 Points: 30,189 Thanks: 18 Thanked 116 Times in 105 Posts	Something isn't right... or you're doing 90 MPH on the highway and driving like a banshee. How are you calculating the mileage? __________________ Zach 2000/2006ish Ford F-250 Larryette 7.3 Powerstroke 4x4 5" Sewer Pipe Exhaust (video clip), DIY 6637 Intake, Wicked Wheel'd, De-foiled, Missing EBPV, Edge Juice with Attitude, X Code Springs, 33" BFGs (SUCK), Alpine W200, Pioneer "D" Series Kevlar 6x8"s, Sirius Satellite Radio, 12" Memphis Pro Audio Subwoofer. 20x10 Mickey Thompson Classic IIs, waiting on tires SLAPS Member #153 Just because I kiss the prettiest girls and I drive my truck too fast, why does everybody want to kick my @ss? Donut Video

04-14-2010, 03:13 AM	#5
300Merc Junior Member Threadstarter Join Date: Feb 2010 Posts: 7 Points: 1,028 Thanks: 3 Thanked 0 Times in 0 Posts	im usually cruising at around 65 mph and im pretty easy on the throttle __________________ Early '99 ford f-250 Powerstroke DP Tuner, Isspro Guages Pyro, Boost, Trans Temp MBRP 4" exhaust Exhaust Brake Mod, TC Lockup switch, 315 75 R16 tires, leveling kit 1983 Mercedes Benz 300D

04-16-2010, 04:20 PM	#6
jermort jammer Join Date: Mar 2006 Posts: 44 Points: 14,808 Thanks: 1 Thanked 1 Time in 1 Post	yep, that's low My truck has never, never got above 18.5 mpg. In defense, I do live at 6,500 feet and there is a 1,000 ft. drop in altitude between me and work. Winter diesel blends usually drop my mileage about 2 mpg. That said, I have been religious about tracking my fuel for the past 2 years and currently see 15.2 mpg average for that time. This includes winter, summer towing of my 7.5 k lb tt and 80 to 90 mph trips to Ill. Yeah, I'd love to see 20 +. Realistically, 16 summer, 14 winter, 13.5 towing. Don't think my #s are too far from the norm. jer __________________ PSD #4 '95 loved it... '97 real POS... 2000 SC SB PSD E4OD 3.73 LS 2011 KR, loaded, Tuxedo Black/Adobe Best Yet!!

04-17-2010, 09:09 AM	#7
van_350sd Junior Member Join Date: Apr 2010 Posts: 5 Points: 293 Thanks: 1 Thanked 0 Times in 0 Posts	You don't have one of those Gray CMP/CPS Units do you? __________________ 2000 E350-Super Duty-ExplorerExt. Mobile LivingRoom-7.3LPSD-3:55LS-Dual AmsoilEaA Air Filters-AutoMeter Phantom Guages-Pyro(Pre)-Boost-Tranny+Hobbs Hour Meter-C2 Pyro(Post) WaterTemp - 4"SS MagnaFlow Wrapped w/ Thermo-Tec 2" Header Tape-SonnaxValve+Tricumulator Shift Springs-Mag-Hytec Tranny+Rear End Cover-1 UpFront Spring Option-Bilstein's-Centramatic's-35 Gallon MainTank+TraxII TransferFlow 27 Gallon Aft.Aux.Tank=62 Gallon Range-ACPM/AIC-DualBattery+Alt-450 FilterMAGx2-Fumoto-ALL Amsoil-Bob's 203*&Billet Housing-Alcoa Classics-Explorer Conversion Installed DynaMat Complete Interior - 4 Leather Captain Chairs/BackSeat/Bed-Hellwig Sway Front/Rear-48"Hi-Lift-C02PowerTank5#SnapOn1/2"ImpactMG725-H3RCleanAgentHalotron2.5#

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