6.0 bad fuel mileage?

smokedout250 · Feb 9, 2012

Okay so my 07 6.0 is getting around
11-12 mpg is this normal? My 450hp7.3 got 15-18.... Whats the problem? The truck is bone stock other than tires which are 275/65r20... Any ideas on what to change? And it doesn't change if u drive like a grandPa or a pisses off teenager..

powersmokin64 · Feb 9, 2012

Fuel filter would be my first guess...

LAXipad · Feb 9, 2012

Same here as the OP. I am getting high 10's with city driving according to the lie-o-meter, and hand calculated at around low 11's. Not a lot of idling and I just replaced the fuel filters when I got the truck.

smokedout250 · Feb 9, 2012

I'll do a full service this weekend!

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Ryan · Feb 10, 2012

Running the SRL, I usually get about 10.5-11 in DC traffic. When I put the stock tune back in, I'm back to 12-13 in the same driving conditions. I change my oil every 5k and have also recently changed my fuel filters. I think some trucks are just thirsty.

FirstSixOh · Feb 10, 2012

What is your water temperature? A thermostat stuck open could be effecting fuel mileage if the engine never gets above 160 to 170 degrees. If you are using 15W40 dino oil, a switch to 5W20 synthetic might help, especially if it doesn't get below freezing in your area. Are you running any fuel additive? I have read good things about AR6100.

smokedout250 · Feb 10, 2012

Water temp is running 190

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yeehaw · Feb 10, 2012

with winter blend i usually got about 12ish around town

FirstSixOh · Feb 10, 2012

Seems as though your thermostat is working. I'm getting only 15 mpg, and I was hoping for better. Might have to go to an economy tune. I have done the math. I need to gain 2 mpg for 10,000 miles to break even on the cost of a Hypertech 43501, or 20,000 miles at 1 mpg. I suppose these numbers are attainable. 15-17 mpg should be possible in a stock 6.0.

FX4 F2-Fifty · Feb 10, 2012

FirstSixOh said:
Seems as though your thermostat is working. I'm getting only 15 mpg, and I was hoping for better. Might have to go to an economy tune. I have done the math. I need to gain 2 mpg for 10,000 miles to break even on the cost of a Hypertech 43501, or 20,000 miles at 1 mpg. I suppose these numbers are attainable. 15-17 mpg should be possible in a stock 6.0.

Ditch the hypertech and get an SCT with custom tunes. Generally your higher HP tunes will net the best MPG. That is if you can keep your foot out of it. Gas milage+Power+happy transmission=happy driver and possibly bald tires.