Bad fuel mileage on 2026 1500 5.7 hemi. Highway driving

Bunk22 said:

My 2023 Ram 5.7 with e-Torque and 3.21 gears got poor gas mileage. It did best with 89 octane but best I saw was 19 MPG on the highway, at 65 mph. If I cruised at 75, I would get 17-18 MPG. Combined, my average was 13-14 on 89 octane. On top of that, I purchased a Ram truck with the smallest gas tank, 23 gallons. My new 26 Ram 1500 Warlock with the Hurricane and 3.92 gears does much better, along with a larger 26 gallon tank.

Click to expand...

Your mpg right in my 2019 neighborhood. 5.7 no e junkola 3:21. If I get on IH 35 and go over 75 mph, forget it. Just FTR 29010 on odometer. I do have heavier Falken Wildpeak AT4Ws in truck.

We’ve never gotten very good fuel economy with our truck. We’re currently in the middle of a drive from central Florida to Washington state. The first two days we averaged right at 17 mpg, from Palmetto Florida, up through the pan handle, through southern Alabama, Mississippi, and Louisiana. Today we drove through Texas, and ended up in Amarillo for the night. We were fighting a head wind for the second half of the drive today, and our fuel economy dropped to 15 mpg.

Lots of people say they get upwards of 20 mpg or more with their truck. Hard to believe but I’m not calling anyone out. Maybe I just drive with a heavy right foot. But when not on a road trip we normally average just over 15 mpg with a combination of 80/20 highway/city driving. Truck is a 2020 Ram 1500 Limited, 5.7 Hemi, 3.92 rear end. Just over 30k miles on the clock.

My 2016 CC 4wd 5/7 w/3.92, 20" wheels with 33" not off road tread tires, would get a max of 17 mpg on the highway @74 mph - MAX.

I have seen a low of 12.5 mpg going across Kansas - quite a few times.
Wind from the front at a 45 deg. angle kills my mpg much more than a direct frontal head on wind.

After doing some underbody panels and other mods, I can see 20-21 mpg with no wind. Average of 16-16.5 mpg in the same conditions that used to get me 12.5-13.5 mpg.

Last year towing the boat to Fl., I was averaging 12.5-13.5 mpg @ 74 mph.

In the humid summer months, I will lose 1-2 mpg after sunset in the southeast.

My truck mpg is very wind/air density dependent - and since it is used almost exclusively on the highway for trips I tend to notice the changes.

Anyone know if it is a software issue for break-in? My '16 5.7 1500 got hand-calculated 16.2 mixed driving for the first 5k miles. Right after 5k got 17.2. Truck averaged 17.2 for the rest of its life, 110k miles.

Locke N Load said:

Anyone know if it is a software issue for break-in? My '16 5.7 1500 got hand-calculated 16.2 mixed driving for the first 5k miles. Right after 5k got 17.2. Truck averaged 17.2 for the rest of its life, 110k miles.

Click to expand...

Not software, mechanical, all breaking in, tolerances not so tight. But each truck is quite literally different. Rear end and your use decides a lot (trim levels/extra doo dads). Fuel, speedometer usage, ie., skinny pedal, driving conditions, altitude, time of year (wat fuel available), what fuel you use (Top tier/middle/Mom n Pop/Octane run (87,89,91), your particular driving habits, where driven (hills/flat) (humidity, winds), could go on and on. Each truck is an individual experience. TOWING add all above and drop those numbers significantly.

CAVEAT: Tires, ride height, suspension mods, rear end all subtract from MPG.

EXAMPLE: I lost 1 - 2 MPG going from stock balloons (road tires) to my Wildpeaks. Everything counts.

All above IMHO.

turkeybird56 said:

All above IMHO.

Click to expand...

Nahhhhh. Its all facts. Period.

I run west coast to east coast 3 to 4 times a year and back. Trip is approximately 1800 miles, from Montana to Tennessee, usually via Minnesota down through Iowa and across Missouri Illinois Kentucky to Tennessee. Total around 4k there and back.

I don't dilly Daly around Montana north Dakota but do slow down in Minnesota. I average in Montana and North Dakota about 14 mpg sometimes 12, depending on wind. Speed is 85 to triple digits.

I'm 24 1500 classic, 5.7, 8hp70, 3.92.and 35s. Stock suspension for now.

In Minnesota I get about 17, Speed 75.

Iowa, I'm on the avenue of America which is a defense road, very well maintained I run about 80, 15 to 15.5. Depending on wind.

Missouri around 80, except near Hannibal where Speed limit is 55. 16, regardless of wind. I'm not certain why, probably flat road

Illinois to Kentucky 16, Speed is 70 to 72, lots of traffic, gas is expensive and multiple opportunities for safe driving awards.

Tennessee, I'm back to 14, average Speed is 80 to 85.

My conclusion from all this

Speed greatly affect mpg, bigger tires affect Mpg, type of gas has some effect but not much, ethanol or non ethanol, and wind impacts more than you know or can figure out.

My last observation, gas/ diesel you have to have it, regardless of price, suck it up, pay for it or sell the truck, stay home and sit on your money.

I for one, cut out other stuff, before I will sit at home, including selling the big ass house, my wife loves, and I don't need for something smaller but I will not sell my truck or not travel.

My humble opinion. Flame suit ready

mikeru said:

We’ve never gotten very good fuel economy with our truck. We’re currently in the middle of a drive from central Florida to Washington state. The first two days we averaged right at 17 mpg, from Palmetto Florida, up through the pan handle, through southern Alabama, Mississippi, and Louisiana. Today we drove through Texas, and ended up in Amarillo for the night. We were fighting a head wind for the second half of the drive today, and our fuel economy dropped to 15 mpg.

Lots of people say they get upwards of 20 mpg or more with their truck. Hard to believe but I’m not calling anyone out. Maybe I just drive with a heavy right foot. But when not on a road trip we normally average just over 15 mpg with a combination of 80/20 highway/city driving. Truck is a 2020 Ram 1500 Limited, 5.7 Hemi, 3.92 rear end. Just over 30k miles on the clock.

Click to expand...

80mph speed limits hurt mpg.

My old 2012 Express got over 18 mpg but not quite 19 mpg. I hand tracked for the first 40k miles. 89 octane, mostly 65-70 mph speed limits. 5.7/6A with 3.92s. With the 8 speed and 3.21 I can see 20 being real possible.

My old 3.55 2012 5.7 sport crew cab got pretty reliably 16.5 in summer 13 mpgs in winter. This was after both sides manifold bolts busted and living in northern Wisconsin. Prior to manifolds breaking I was getting 17-17.5 in summer. RPMs at 1900 at 80mph. With my 26 3.92 5.7 it’s 17mpgs in summer 14 in winter, 2150 RPMs at 80mph. I’ve got a lead foot so there’s that.

Many others already covered this but break in on these Hemis is crucial, and that extends to not worrying about mileage until at least 5k miles in

2022 Diesel just got 23 mpg on a 1600 mile road trip. 3.73 rear end and 6 speed trans.
Max was 23.7.