I commute 500 miles/week to work and school. I have the 2004 F150 5.4. Will I get better mpg going 70 mph or 75 mph? I calculated my first fill up ($70 ) and I came up with 15.75 mpg.

 

how about you go the speed limit.

 

Dude it ain't gonna matter. Buy a cheap commuter car and save big, i did with over 600 miles each week.

 

If you go faster, it will help you to get there before you run out of gas so the economy doesn't matter.

 

Do you have one of those computer displays that show MPG?
If you don't maybe someone who does can see what the difference is between 70 and 75 MPH.

If you get 15.75 driving 75 mph then you would need about 16.75 driving 70 to increase MPG.

Here is my question which I've asked before and didn't get an answer.
What is the overall optimum MPH for maximum fuel economy?

Situation:
You have to cross the desert (50 miles across)
Your truck has one gallon of gas.
You know it will not get 50 MPG.
You will have to walk some of it.
You want to walk the least distance possible.
How fast do you drive?

 

couldn't agree more, best thing I ever did, my Kia scores me 40mpg on highway, easly pays for itself in just the cost of gas...

 

is it all flat? id go about 10 miles at 55mph then hit top speed and shut off the truck and coast as far as i could lol

 

The faster you go, the more wind resistance has an effect on your truck. Same thing applies to any vehicle for that matter. I can drive my bike at 55-60 mph and get 50 mpg, drive it at 65-70 and it goes down to 45 mpg. Same rules apply to the truck. If I can average 60 mph in my truck on longer trips, I'll get anywhere from 18-20 mpg. But if I drive 70 mph, the mpg drops to 17-18.

 

buy a friggin VW and sell the truck if you are worried bout the MPG

 

Its some where between 40 and 45 mph, But your economy doesnt really start to drop untill you break 55-60.

 

Let's see, you could pump the tires up to about 100 psi then cut all the tread off except the center one. Remove the side mirrors, radio antenna, tailgate and every ounce of extra weight. Lower the truck to within an inch or two above the ground and add skirts. Tune the motor to within an inch of it's life. Rent a wind tunnel for a day or two to find the optimum speed with the lowest drag. That should do it.

Russ

 

I'd say the best speed would be however fast you're going when the truck shifts into OD. Keep the lowest speed possible in OD that allows the tranny to stay in OD without downshifting often. I would think that MPG will be best with the lowest RPM possible in the highest gear.

 

Buy yourself a motorcycle, dude, you'll be getting like 70MPG on a good day. If you buy a truck, the term MPG leaves your vocabulary except as a diagnostic tool.

 

i was at school and there was someone talking about their mpg and they were complaining because they were getting 21 mpg. this kinda made me mad because i only get 10. ive thought about getting a car but i couldnt stand riding that low to the ground.