Yes, you can get better 7.3 MPG and Horsepower.
Compared to a standard gasoline engine, a Ford F250 equipped with a 7.3 diesel engine is generally more fuel-efficient—i.e. you'll get better 7.3 Powerstroke MPG than say an F250 equipped with a gasoline V10.
Since diesel fuel stores about up to 15% more energy than gasoline, your 7.3 Powerstroke diesel will, properly driven, get around 30% better MPG than that F250 V10.
But, since most places I looked, including fueleconomy.gov and Nada guides state that "EPA Fuel Economy MPG estimates not available" for the 7.3 Powerstroke, I had to do some digging to find averages that I'd consider reliable.
Since most of the 7.3 MPG information out there is second-hand heresy off of forum posts anyway, I used number averages from a site called fuelly.com. Using their tools I got a lump sum average from tens if not hundreds of actual 7.3 diesel owners, stating their own experience with miles per gallon fuel efficiency.
Here's what I found:
Fuelly.com states that "Based on data from 92 vehicles, 5,396 fuel-ups and 1,822,710 miles of driving, the 1999 Ford F-250 Super Duty gets a combined Avg MPG of 14.82..."
Fuelly.com states that "Based on data from 92 vehicles, 3,981 fuel-ups and 1,223,722 miles of driving, the 2000 Ford F-250 Super Duty gets a combined Avg MPG of 14.07..."
Fuelly.com states that "Based on data from 66 vehicles, 3,750 fuel-ups and 1,010,890 miles of driving, the 2001 Ford F-250 Super Duty gets a combined Avg MPG of 13.62..."
Fuelly.com states that "Based on data from 68 vehicles, 5,084 fuel-ups and 1,838,593 miles of driving, the 2002 Ford F-250 Super Duty gets a combined Avg MPG of 13.38..."
Fuelly.com states that "Based on data from 17 vehicles, 1,362 fuel-ups and 395,452 miles of driving, the 2003 Ford F-350 Super Duty gets a combined Avg MPG of 12.79..." and for the 250 "Based on data from 31 vehicles, 1,140 fuel-ups and 332,545 miles of driving, the 2003 Ford F-250 Super Duty gets a combined Avg MPG of 12.59..."
And finally, I looked up all model years of 7.3 Excursion and averaged their diesel MPG. Out of 119 Ford Excursions that provided 2.9 million miles of real world fuel economy Ford Excursion 7.3 diesel MPG reportedly averaged about 13.8 MPG.
97 Ford F-250 Super Duties provided Fuelly.com with 1.2 million miles of real world fuel economy & MPG data. Over the entire span of their production range, 1999-2010, And Ford V10 gas engines produced a reported average MPG of between 8.1 and 11.7 MPG.
Which holds true with our data of 7.3 Diesel MPG, at roughly 13-14 MPG, averaging around 25-30% better than a similarly powered gas engine.
A few things about these 7.3 MPG stats:
First, all theoretical statistics on MPG are complete BS—only your own field data is reliable for you. Because the way you drive, the quality of the diesel fuel you put in your vehicle, and how well you maintain your engine are what will truly determine your own results.
That being said, a few things to keep in mind:
After surfing more 7.3 MPG data and stories than is healthy, the personally reported fuel efficiency numbers for most 7.3 Powerstroke diesels seem to fall somewhere in the 13 City/ 18 Highway range.
If you surf the Internet for 7.3 Powerstroke MPG, you're going to come across forum posts that reference "hand-calculated" miles per gallon.
Simply put, and at the risk of being too comprehensive, here's what hand-calculated MPG means and how it's done:
I know that was too basic, but someone was going to ask me, so ... there it is.
A 7.3 guy goes into the grocery store, and...
(Already heard this story? Scroll to the bottom of the page to read how you can get more mpg and horsepower from your 7.3 diesel)
Way back in 2007-2008, the average US price for diesel fuel skyrocketed. To make matters worse, my wife and I were living in San Jose, CA at the time.
Now, it's a gross understatement to say that California politicians love their gas taxes. A fact that makes a California diesel fill up one of the most expensive in the nation. Doesn't matter if gas prices are up or down, sunny beaches, movie stars, and "free" stuff for everyone apparently costs money.
And since they can't make the electric car drivers pay for it, that leaves you and I and our nasty diesel trucks to foot the bill. Ah, a rant for another day...
Back to 2007-2008 diesel fuel prices...
Bay Area diesel pump prices were constantly "topping-off" at over the $5 per gallon mark. And my 2002 Ford F350's 7.3 diesel mpg being what it was... At best my F350's fuel economy was 15-16 mpg highway and somewhere below 12 mpg in Silicon Valley's "pause and putter" traffic.
Let's just say that driving my truck for anything beyond absolute necessity was painful on the pocketbook.
So when my wife casually asked if I'd run to the store and get bread for our kids' lunch sandwiches the next day, I froze up. Then I quickly did some tricky math in my head, At 10 miles per gallon, for almost 20 miles round trip, that's...
Now, I'm no "Ford genius engineer", but by my calculations that single loaf of bread was going to cost $13 by the time I got it back to the house.
What happened, you ask?
Well, I mumbled something to my wife about "this not being Russia and bread shouldn't cost … blah blah." Then I diligently went and got the bread, of course. Not the point.
But since I was certainly not selling my diesel to buy a Tesla — it won't tow a trailer — something had to be done. That's when my interest in increasing my 7.3 Powerstroke's mpg started.
Mandating increases in fuel economy is an American government obsession. And the very death of your 7.3 Powerstroke diesel engine's production run is a direct casualty of that obsession.
These days, you're dealing with tougher than ever emission standards. If you were prone to conspiracies, you'd think that "they" don't want you driving anything but an electric thimble up and down the roads. Nah, that can't be, right?
But believing that you can get more horsepower from your 7.3 Powerstroke while at the same time increasing its mpg? That's just lunatic talk right there … isn't it?
However, better mpg at the sacrifice of horsepower doesn't have to be your only choice.
In the articles below, you'll discover 7.3 upgrades you can install to increase your 7.3 Powerstroke's horsepower without sacrificing fuel efficiency.
Read these articles and never buy $13 loaves of bread again: