How to get better gas mileage from the 7.3?

I am having the same issue. I am just shy of 1,000 miles on the odometer. I have never achieved anything better than 8 mpg (not towing). That is calculated mpg, not the truck computer. The truck computer does indicate the same. I drive as easy as possible and use eco mode.
As soon as I reach 1,000 miles, I am going to take it to the dealership and have it checked out because there must be something wrong with the truck.
I have repeatedly checked with my scanner for any codes or issues and nothing is showing. I have also checked to be sure that the front axle is disengaging. None of the wheels get hot, so the brakes are not dragging.
I have seen here on the forum over time that a few people have posted about the same issue.
If anyone has any ideas on what is causing the low MPG, please let me know.
I don't have a 7.3, I have the 6.7 but I think it's still applies. When I first got the truck I couldn't get better than 18mpg highway and averaged around 17mpg... I never calculated because I don't care that much. The truck now has 5k miles and I am getting about 22 or 23mpg highway and average 20 or 21mpg. So I'm thinking the truck needs to break in some. Hopefully you start to see 12mpg or whatever the 7.3 people claim.
 
I can say when I jumped in I'm 63 retired already had my diesel fun I knew I wasnt going to get 30 mpg. I love steppin on the throttle in tow haul mode. I did a long trip and did slow accelleration not going over 60 and the fuel economy was much greater. But I say fuk it, I love rippin around full throttle. That said I'm retired, my house is paid the truck is paid. I get the concern of younger folks. When I was younger with bills I had a smaller higher mileage vehicle. Couldnt afford a superduty
I kind of took the same approach when I decided on the 7.3 Tremor. Wasn't interested in another diesel in the least. Always loved big blocks. Who ever heard of a big block that got good mileage? Who ever bought a muscle car, either in the 60's or today, that was concerned about mileage. I'm out to enjoy my senior years in my dream truck of my 20's. It's a 7600 lb 4WD truck with an old school, get up and get your a$$ down the road big block, and I love it every time I get the urge to burn a little extra petro and feel it in the seat of the pants. And I love the sound of that V8 going through all 10 gears. I feel 19 years old every time I give in to the urge. Makes my wife giggle too. 😁 Look out America, grandpa's got his hot rod truck! 🍻 👊:cool: 🇺🇸
That makes 3 of us. 61 and on the rocker out front. Hoping against hope that I will get the 7.3 gasser by summer. Already have the hot rod car and now grandpa has the hot rod truck on order. Can't wait to burn that gas and hear that V8 roar! 😆
 
There is no way you should be getting 7.8 across two tanks unloaded.
I would agree with you. I've run the numbers based on the fuel receipt at the pump (Ignoring the computer)
 
I had 2016 3.5 eb before the Godzilla. I put a cold air intake and cat back exhaust and picked up 4 mpg easily. Would the same apply to a 7.3 or was my previous experience helped by the turbos?
 
Yea. Not looking for smart ass comments.
Well it’s pretty much a dumb question to ask. Hmmmm let’s see. It’s a big block V8, full size truck, rolling 35’s or 37’s in my case and basically a brick on wheels. But I should get 20+ miles per gallon. If your looking for better MPG’s by a Honda.
 
Well it’s pretty much a dumb question to ask. Hmmmm let’s see. It’s a big block V8, full size truck, rolling 35’s or 37’s in my case and basically a brick on wheels. But I should get 20+ miles per gallon. If your looking for better MPG’s by a Honda.
You could have all that with a diesel... And not have to get a Honda.... Just saying
 
Well it’s pretty much a dumb question to ask. Hmmmm let’s see. It’s a big block V8, full size truck, rolling 35’s or 37’s in my case and basically a brick on wheels. But I should get 20+ miles per gallon. If your looking for better MPG’s by a Honda.
I’ll quote myself from an older thread as to why “How to improve fuel economy?” isn't a dumb question to ask. In fact, it’s perfectly reasonable.

Asking about gas mileage is perfectly reasonable for two reasons:
  1. It impacts range. The more fuel efficient the truck is, the more range you get. This is particularly noticeable with the 7.3 while towing since it only comes with a 34 gallon tank.
  2. If the truck is still plenty capable with the more fuel efficient gears, why not save some money on gas? Otherwise you're almost literally burning money for the sake of it?
That second point is what gets me. Regardless of whether we're talking about a Prius or a semi truck, saving money is valuable and logical. If the truck will comfortably do what you need it to do while also saving money on gas, that's purely a win. So it's entirely reasonable to ask about the more fuel efficient option.

Another way of looking at it: if I saw someone with a fire pit in their driveway and throwing real money into it, I would seriously question their sanity. With a truck you're one step away from directly burning money. Now, obviously we get use from the fuel we burn but if you're burning extra completely unnecessarily, then you start to look like the person with the fire pit in their driveway.


Similarly, are semi drivers who seek to buy trucks with better fuel economy dumb? They only get single digit fuel economy when towing.

Now, if someone asked “How do I get 30mpg out of my 7.3L?” then that’s either a gross misunderstanding of what they purchased or a dumb question. But that’s not what OP asked.
 
I went from a 2018 2.7 EcoBoost getting 17.3 to the 2020 7.3 godzilla getting 13.5. It's to be expected when you go from feeding a rabbit to feeding a horse. Can't expect fuel economy from a big block. I'll be happy to get close to 15 after I put my cold air intake and Borla exhaust
Which cold air intake and Borla did you install and did it make a difference in MPG?
 
I had 2016 3.5 eb before the Godzilla. I put a cold air intake and cat back exhaust and picked up 4 mpg easily. Would the same apply to a 7.3 or was my previous experience helped by the turbos?
Intake and exhaust would not get the same results from a NA engine compared to turbos.
 
Depends on what is defined as good for a heavy gas truck. I've been pretty militant about making sure my tire pressure is correct and I don't speed from stop light to stop light in town driving. Cruise control everywhere I go - basically I drive like a 90 year old.
I attached a spreadsheet I started to track mileage - this bypasses the computer and is just straight hand calc. I don't have the tremor as I have the 3.55 rear end but it could help as a good baseline. Also, eco mode all the time.

Fuel Tracking | 2022 7.3 Gas Superduty 3.55 | Purchase date 10/26/21
Total SpendAvg Price/GalAvg MPGOverall Mileage
DatePrice/GalGals InSpendMilesMPG
$2,343.02​
3.76514.369,570.7
5/6/20224.49918.6$83.87305.516.39
5/3/20224.49913.8$61.91226.516.46
5/1/20224.49912.2$55.00210.817.24
4/30/20224.4911.1$49.38139.512.57
4/24/20224.29916.3$69.9423914.69
4/20/20224.29917.6$76.01227.912.95
4/16/20223.87919.1$73.92195.210.24
4/15/20224.29913.7$58.69196.714.41
4/10/20224.29915.7$67.36211.813.52
4/3/20224.35916.3$71.25233.614.29
3/28/20224.4919.3$86.87276.614.33
3/20/20224.59913.4$61.50187.214.00
3/15/20224.59917.2$79.08258.915.06
3/2/20223.56919.6$70.00289.814.78
2/25/20223.51911.8$41.63164.513.91
2/17/20223.49916.0$55.97228.614.29
2/10/223.49913.8$40.15198.814.4
2/4/20223.44914.6$50.3219613.4
1/27/20223.35916.4$55.00247.715.1
1/22/20223.359
19.9​
$66.80​
288.80​
14.5
1/14/20223.359
17.4​
$58.57​
234.10​
13.4
1/5/20223.359
44.7​
$0.00​
541.20​
12.1
12/29/20213.699
19.6​
$72.39​
225.40​
11.5
12/28/20213.299
20.6​
$67.80​
317.20​
15.4
12/26/20213.299
12.8​
$42.23​
180.50​
14.1
12/20/20212.399
17.4​
$41.79​
282.90​
16.2
12/17/20213.639
14.0​
$50.94​
196.10​
14.0
12/15/20213.299
16.0​
$52.68​
232.70​
14.6
12/12/20213.399
12.0​
$40.87​
167.00​
13.9
12/6/20213.459
13.2​
$45.77​
204.50​
15.5
12/2/20213.499
15.8​
$55.29​
235.90​
14.9
11/28/20213.549
12.5​
$44.39​
182.90​
14.6
11/24/20213.549
24.3​
$86.21​
343.00​
14.1
11/17/20213.599
20.5​
$73.73​
298.00​
14.5
11/13/20213.599
27.5​
$98.80​
424.90​
15.5
11/7/20213.599
22.9​
$82.55​
322.90​
14.1
11/7/20213.759
17.5​
$65.64​
298.10​
17.1
10/30/20213.359
26.4​
$88.73​
360.00​
13.6
 
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Two days after I picked up my truck. I took a short, 150 mile road trip to visit my parents. Since I was in the break-in period, I decided to (at least for a little while) take it seriously and avoid the interstates. I stuck to the state routes that are mostly 55 mph or below. With my brand new truck, I actually saw 15.1 mpg. That was over a large stretch where there weren't many towns to slow down through. When I got around towns and had to vary speeds more, it was down to around 14. On the way home, I threw caution to the wind and took the interstate home. Alas, I also had a 20 mph headwind. My mileage dropped below 13 mpg for the trip back home. Since then, I've made additional trips on the interstate without significant headwinds and, running 70-75 mph, I get about 14.1 mpg (14.0 if I hand calculate it).

The bottom line is that this truck, like many vehicles, sees it's best mileage at around 55-60 mph. When you go above that, you're going to start to see your mileage drop. But, there is a caveat: the brick-like nature of the vehicle means that wind direction plays a role too. So, at 70 mph, a 20 mph head wind gives you the equivalent drag of driving 90 mph. Alternatively, drive 70 mph with a 20 mph tail wind make for a drag of approximately a 50 mph driving speed.

-SR-
 
Drive it like you stole it and enjoy
Don't worry about mileage, ever!!!
You have a bad ass truck! Put the digital speedometer on, and never look at your mileage again
Only know that if you're on the interstate, you might get a little better than 12 for the duration, so be happy about that
 
Drive it like you stole it and enjoy
Don't worry about mileage, ever!!!
You have a bad ass truck! Put the digital speedometer on, and never look at your mileage again
Only know that if you're on the interstate, you might get a little better than 12 for the duration, so be happy about that
Kinda have to agree. You don't by a Corvette, a '70 Barracuda, or in this case a big block muscle truck and worry about mileage. Know what to expect and drive it. You spent 70-85 grand for a truck. Drive it like you can afford what you bought. It's like building a million dollar house and than worrying about the cost of curtains. :eek: 😜 🍻

(Sorry folks, feeling a little frisky today!)🥃:cool:
 
Drive it like you can afford what you bought.
THIS.👆

Always find it humorous when the ballers cry about fuel prices...like, I thought you all were Scrooge McDuckin' it back at the castle. lol.
Gotta pay to play, kiddos.

[Edit] That said, the 12mpg I'm getting stings because I know it's gonna be single digits towing.
...but not cause fuel cost, I'm dreading stopping at the car pumps w/a camper in tow so often.
 
THIS.👆

Always find it humorous when the ballers cry about fuel prices...like, I thought you all were Scrooge McDuckin' it back at the castle. lol.
Gotta pay to play, kiddos.

[Edit] That said, the 12mpg I'm getting stings because I know it's gonna be single digits towing.
...but not cause fuel cost, I'm dreading stopping at the car pumps w/a camper in tow so often.
Yes it's all relative. Fingers crossed the new replacement tank is available very soon. Man is that baby going to be fun to fill up! 😜 But at least you won't have to fuel every two hours. 🍻
 
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Yet it's all relative. Fingers crossed the new replacement tank is available very soon. Man is that baby going to be fun to fill up! 😜 But at least you won't have to fuel every two hours. 🍻
I'm looking forward to it. When not traveling, I don't drive much and usually just end up topping off w 3/4 of a tank left whenever I happen to be out and have time...easier to swallow that way. Filling the bigger tank on a trip might be a bit of a nut punch, but it's all the same in the end.
 
Some guys on FTE that swap the non-Tremor air dam report 1-2mpg loss, yet others say they don’t notice. Personally, I would expect the ones who claim the 1-2mpg loss are more in line. Maybe the ones that claim no loss drive with their toes sticking through the grille and wouldn’t notice anyway?

I like my truck getting good mpg, so I’m keeping my stock air dam.
 
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