Driving home from the ranch today and decided to reach up and set the Scan Gauge to current average MPG and hit the reset button. Cruise control set at 67 MPH, the truck averaged 17 MPG. It did drop down to 16.8 at one time but worked its way back to 17 shortly there after.
Now the catch, once I pulled off the interstate (I-35E south of Dallas) and had to begin rowing through the gears everything went to HECK (wasn't sure if I could say hell). Turned the Scan Gauge to read instant MPG and noted that when rolling throught the gears, but by no means running hard the MPGs would drop below 4 MPG. OK as low as 3.2 MPG, there I said it. Of couse while coasting it would also read up into the low 30s. MPG. Over all it must spend more time in the extreem low MPG area because my over all MPG for the last two tanks seem to be 12.9 MPG. However this 12.9 also includes a lot of very slow moving around the ranch as well as a lot of stop and go to avoid hitting the small herd of new born calfs and avoiding the 200 plus horns of the Longhorn who are very sure I have hundreds of pounds of feed in the bed of the truck.
Moral of the story, next time you want to complain about your V-10 MPG, only figure the mileage on the highway with the cruise control set.....It will make you feel good up until you hit the exit ramp anyway....LOL!!

 

I agree that on the highway you can get excellent MPG but stop and go traffic kills the MPG. Keeping my truck at 65mph/2000rpm I can get 15+MPG. But in town 9mpg is hard to avoid.

 

only real world way is reset the trip meter or write down the speedo milage at fill up. drive to normal refill miles for a tank.refill. divide miles driven by gals used to get the real mpg reading.
yes the v10 is very capible of 17 or 18 on a straight normall drive. i also have gotten that much.
the guages we get as a on needed do dad. messure flow and change that to mpg's. in stop and go city. that guage never reads correctly just as on a boat. they read fuel flow to get gals per hour. i've had mine say i was using 18 gals a hour running hard."the tank only holds that much. on a easy run tell me i was useing 2 or 3 gals a hour.
i use my hour meter.write down what it reads when full. run what every hours that day ,refill the tank and divide hours by gals really used . easy running it will normally use at 3k rpm just under 2 mph or run all day never shuting it off when dirfting for blue fish or fluke. hour meter saying 6 to 8 hours and only put back in 6 gals for the 6 to 8 hours,

guess what i'm trying to say is don't trust them. and your v10 could very well be giving you 17 mpg's real world on the highway. fact is my 05 would almost always on a long trip here get 18 tops 16 to 18 a normal.

 

Real EYE opener is to reset the computer on a highway on ramp, and run her thru the gears...
Then look up!!!!
Not a recommendation to do this...

 

I reset mine while coasting down a 7% grade once. 52 MPG is awsome!

But I have had it read over 16 MPG several times when I reset it and a level highway, with light traffic going about 65 MPH or so. This is over a 12 mile run. Once I start up the short 6% grade to home, it will drop to 13.5 by the time I get to the driveway.

It once read over 17 on a 8 mile run at 50-55 mph on the 2 lane FM roads.

Average in the mostly mixed driving I do is a solid 12 MPG, driving with no regards for economy.

 

You cant really go by the instentanious readings for anything usefull... even on our lexus RX300 which has a 3.0L it will read 3-4mpg on average acceleration and 100MPG coasting.

Thats cool you V10 guys can get 16-17 on the highway though... even my itty bitty 4.2L in my little reg cab short bed doesnt break 16 anymore on the highway, it did a few times a few years ago, but the last couple years hwy mpg 15-16 (and city in the 14's). Winter less than that.

 

i made 17 mpg before driving a cruise controlled.68 from reno nevada to los angeles calif..like 300 miles..but i only did that once..usually 14 to 16mpg hwy

 

Well, last weekend, I crowbar'd the wallet open and filled 'r up, resetting the MPG 'puter. Then hit the road with cruise set at 75, drove about 140 miles. 'Puter indicated 15.7, but upon refilling it was really only 14.8...which I'm wont complain about. I'd say for an average SUV that's fairly respectable...but this one isn't average!