Bad fuel mileage 5.7 hemi

[19reb]

I'm none too happy about the mileage at this point. Not really sure what changed. Was getting 13.1-13.4 city with a max speed limit in my area(20 mile radius) of 45 and mild spirited driving. Now getting 12.6-12.9 with zero changes.

So we decided to take it on the highway to stretch it's legs a bit further. Both myself and my wife drove it. A night and day difference in driving styles, as I'm sure most of you can relate. Neither of us could get the MPG on the dash higher than 14.3 for a 150 mile stretch with 135 miles freeway and 15 rural. I drove to and she drove from, both 150 miles each. I could only get 13.1 in that 150 mile stretch. Literally the only way my wife was able to achieve the seemingly impossible task of getting 14mpg average, was by driving 10-15mph slower than the speed limit on the highway using cruise. If she put her foot in it at all, it dropped a tenth.

This is with, now, 2146 miles on the odometer and using 87 octane fuel. I gotta say, I knew what I was getting in to before I got in to it. But I also know these trucks have changed leaps and bounds in the last few years. The last Ram I owned was a 2012 1500 Sport 4x4 and we got 19-21 highway and 13-14 city and that was with the 545RFE transmission - the last year they used it.

I expected and truly expect these trucks to be way higher efficiency than my 2012 Sport 4x4. At least match it! Should I not? My Rebel build date is 11/18. I didn't buy this with MPG in mind, but damn, man! I at the very least expect to get what they advertise the damn thing to get - 15/city 17/comb and 21/highway or somewhere really close to it...

FFS, my Hellcat Challenger got 15mpg in the city with the same driving style and 23-25 highway mpg at 90mph. My wifes 2015 Durango R/T gets 16-18 city with pretty much the exact same engine and transmission. It's a negligible weight difference too. Because they pretty much weigh the same. The Ram being only 300lbs. or so heavier. My 2015 Scat Pack Challenger(6.4/392) got better mileage than this Rebel does and it was a true hog. Never could get more than 15mpg out of it, no matter what I did.

I can honestly say these mpg numbers on my Rebel match what I got from my 2005 Dodge Ram 1500 before I modded the **** out of it. Not very impressed to say the least.

Yes, we used the on board computer as our calculator. They put it in there and expect you to think it's accurate, right? Should it not be accurate? I hand calculated numbers with my Hellcat and the wifes Durango and they were spot on correct. The only reason I did those was because I couldn't believe it was so good on either vehicle for obvious reasons. Seems I vaguely remember hand calculating it on my 2005 and if I remember correctly, it was very off. Is it not reasonable to believe the on board computer can actually handle these types of tasks these days? I mean, it is 14 years later and we do pay a lot of money for these trucks...

Does anyone elses Ram feel like it struggles to stay at highway speed? Really the only time I see the ECO light come on is when I make it come on or I coast for a long while. It's peppy, though, I'll give it that. Those 3.92 gears are pretty killer for street use. I love em'!

MPG aside, dude, I love the truck and only wish they would put the 6.4 in these and retire the 5.7. I absolutely hate the 5.7 Hemi and this, among many others, is the biggest reason why.

 

[Zinger]

Three tanks in and my hand calculated mileages have been 15, 13.5, and 14.1 MPG. The computer calculated mileage keeps getting further optimistic as I go, at 15.1, 14.1, and 15 MPG. Mostly the same driving terrain across the board.

I expect it will bump up a bit now due to the warmer weather, but for comparative purposes my 2003 Expedition with 5.4l I would get 13-14 MPG with the same type of driving. My Rebel is heavier, and has off road tires, so I guess it's an improvement, and in all honesty what I expected. However, the Expedition was only rated at 14 MPG!

This truck has way more drag, you can feel it. I can't say if it's the tires, trans, rear, aerodynamics, or a combination of all, but it definitely can't be helping MPG. I looked at my rotors today, 1250 miles and they are brand new. See attached pics. At this rate I'll never need brakes. A combination of the high rolling resistance and eTorque braking I imagine. Perhaps the silver lining in all this.

 

[Creep0321]

Drove from NC to TN yesterday, wife, 2 kids and about 500 lbs of gear/luggage. Computer showed 18.1 first 1/4 of trip using cruise control, 70-75mph, hand calcd to 17.8..... second 3/4 trip didn’t use cruise control, still averaged 70-75, computer showed 19.1, haven’t filled up to hand call yet though.

 

[Raylan GIvens]

I was worried about the fuel economy after reading this site, but so far I have been getting about 18 mpg in the first two days. The real test will be getting through traffic tomorrow going to work, but so far no issues. Hemi ETorque w/3.92 gears

 

[kittyjo]

Today trip highway 75-85 and backroads 55-60

 

[Ramit71]

I get 16-17 in my rebel

 

[MFALRAM]

Here’s a trip going to Lake Placid and back. All sorts of hills I was pleasantly surprised how well the mpg was.

 

[19reb]

Here's mine as of this morning. 2019 Rebel 12.

 

[Electrical]

I have the same 5.7 in my Durango and just got back from a 2,400 mile roundtrip. In one leg of the trip I logged 603 miles on a tank and then pumped 23.1 gallons into it which calculates to 26.1 mpg. My Durango, according to the door sticker, weigh's just shy of 6,000 lbs. I use ethanol-free gas and kept speeds in the 65 mph range. OEM tires with pressures elevated to 38 psi cold.

Whatever is going on is not the fault of the engine, or so it seems to me. When running right the 5.7 is capable of phenomenal fuel economy.

 

[19reb]

I drive the speed limit and don't use excessive acceleration. I don't know what I could be doing to get such disgusting mileage. I've tried everything to make it better. I've tried every type of fuel and several different types of driving styles. Even tried a different driver, nothing works. I own a Durango R/T my wife drives. She manages around 18 city. The door sticker doesn't tell you the curb weight of the vehicle. Just max weight rating. My Durango weighs 5400lbs. with a full tank and 2 passengers according to the scale at Flying J. I can see the AWD Durango weighing another 100lbs or so. No way a Durango weighs as much as a Ram 1500 4x4(5800lbs.).

 

[Electrical]

I drive the speed limit and don't use excessive acceleration. I don't know what I could be doing to get such disgusting mileage. I've tried everything to make it better. I've tried every type of fuel and several different types of driving styles. Even tried a different driver, nothing works. I own a Durango R/T my wife drives. She manages around 18 city. The door sticker doesn't tell you the curb weight of the vehicle. Just max weight rating. My Durango weighs 5400lbs. with a full tank and 2 passengers according to the scale at Flying J. I can see the AWD Durango weighing another 100lbs or so. No way a Durango weighs as much as a Ram 1500 4x4(5800lbs.).

Subtract payload from GVWR; it's a surprisingly good estimate of vehicle weight (see the thread "post your door stickers" or some such name like that).

 

[Jeff270]

I am on my second tank of gas, around 550 miles total. MPG reads 17.9

 

[SilverSurfer15]

one thing I’ve noticed that will kill your mileage is cruise control, it’s fine for flat ground but through rolling hills it will destroy your mpg figures as it goes 75% throttle up small hills trying to maintain a certain speed constantly. As where manually you can just bleed off 3mph and stay in overdrive and keep the mpg up.

while this happens in most vehicles, it’s really noticeable on this ram. The instant mpg will drop to like 6 while it goes wild on the throttle

 

[Jbird]

I drive the speed limit and don't use excessive acceleration. I don't know what I could be doing to get such disgusting mileage. I've tried everything to make it better. I've tried every type of fuel and several different types of driving styles. Even tried a different driver, nothing works. I own a Durango R/T my wife drives. She manages around 18 city. The door sticker doesn't tell you the curb weight of the vehicle. Just max weight rating. My Durango weighs 5400lbs. with a full tank and 2 passengers according to the scale at Flying J. I can see the AWD Durango weighing another 100lbs or so. No way a Durango weighs as much as a Ram 1500 4x4(5800lbs.).

Have you tried resetting the ecm? Might clear out some bugs causing the poor mileage

 

[19reb]

Have you tried resetting the ecm? Might clear out some bugs causing the poor mileage

How would one go about resetting the PCM on these trucks? Pull the negative cable for 20 minutes or so?

 

[YawnY]

How would one go about resetting the PCM on these trucks? Pull the negative cable for 20 minutes or so?

Pull the positive and negative cable, touch together for approx 5 minutes. Discharges power stored in all modules. Also good for clearing engine lights.

 

[Chris]

Pull the positive and negative cable, touch together for approx 5 minutes. Discharges power stored in all modules. Also good for clearing engine lights.

I can only imagine the light show this will cause on an etorque truck.

 

[19reb]

Pull the positive and negative cable, touch together for approx 5 minutes. Discharges power stored in all modules. Also good for clearing engine lights.

As an FYI, these instructions didn't even reset the radio. It did absolutely nothing. Even let it sit for 30 minutes. I didn't think it would to be honest. Because those are the exact instructions for resetting the PCM on my 1994 Ranger and I have a hard time believing it would be the exact same instructions for a 2019 Ram.

Anyone else know how to reset the PCM on these new trucks?

 

[YawnY]

As an FYI, these instructions didn't even reset the radio. It did absolutely nothing. Even let it sit for 30 minutes. I didn't think it would to be honest. Because those are the exact instructions for resetting the PCM on my 1994 Ranger and I have a hard time believing it would be the exact same instructions for a 2019 Ram.

Anyone else know how to reset the PCM on these new trucks?

As an FYI, these instructions didn't even reset the radio. It did absolutely nothing. Even let it sit for 30 minutes. I didn't think it would to be honest. Because those are the exact instructions for resetting the PCM on my 1994 Ranger and I have a hard time believing it would be the exact same instructions for a 2019 Ram.

Anyone else know how to reset the PCM on these new trucks?

The internal memory might have its own data saver or have its own internal battery to avoid losing data if the battery is disconnected. If that didn't work then it might have to be done with a scan tool like the Chrysler star scan. I'm not 100% certain as I've been out of the automotive field as a journeymen for about 5 years, but you might need a scan tool to reset the fuel trims.

 

[19reb]

The internal memory might have its own data saver or have its own internal battery to avoid losing data if the battery is disconnected. If that didn't work then it might have to be done with a scan tool like the Chrysler star scan. I'm not 100% certain as I've been out of the automotive field as a journeymen for about 5 years, but you might need a scan tool to reset the fuel trims.

Exactly what I'm thinking. Thanks for the help, by the way. I've tried now several different ways and nothing works. It's confusing because I've read here and other places of other 2019 owners who have just disconnected their negative cable and everything reset. I've taken the battery completely out and nothing resets it.