Hi, owner of a (used, 100,000 km, about 60,000 miles) 2012 RAM 1500 Crew Cab Big Horn,
5.7L Hemi, used as a secondary vehicle.

Previous owner took meticulous care and truck is in almost brand-new condition, a pleasure to drive.

The gas mileage in this thing is abysmal. I know that I didn't buy an economy car, but Jesus, you can
almost see the gas needle moving down as you drive. One fill-up I drove only 150 kilometres (about
90 miles) and it took 75 LITRES (20 GALLONS!!!) of gas. Yes, it was stop-and-go in the city, but ...
What the hell????? And NO, I do NOT drive with a lead foot -- quite the opposite, actually.

Even under regular driving conditions, I am using 16 -20 litres per 100 km (12 - 15 mpg),
and most of the time it is closer to 20 (12 mpg) than 16 (15 mpg). Thank God that at least
it runs on regular!

And this is in good weather in 2-wheel drive. I shudder to think what will happen this winter,
especially if I need to use 4-wheel high on snowy streets, or what will happen if I actually
want to tow something. Once again, I know this not an economy car, but ....

So. Bottom line ... any opinions? Is this normal? Are all of you getting the same abysmal
gas mileage as I am? Do any of you know any fixes that might help? Any feedback would
be much appreciated.

Thanks :-)
Sam

 

i was getting roughly the same with my 2012 4.7, I went and got a tuner to see if there was a difference. There is but it may not be your route to go. I have also tried that royal purple stuff you put in your tank. That worked a bit as well

 

Thank you ... not sure what the "Royal Purple" stiff is, but I'll check it out.
Thanks again for your reply, it is appreciated :-)
Sam

 

Head down a straight smooth highway and get up to 100 kph. Ease the truck into neutral and see how it acts. Does it coast and slowly lose speed or does it slow down right away. If you have a brake dragging, it will slow down fast and slurp fuel fast. If it's doing this, go for a long drive and then stop somewhere and feel the wheels with your hand. If one is a lot warmer, or hotter, than the others, that may be the one dragging. Since you're metric, I'm assuming you're up in Canada. Your park brake cable might be the culprit.

Do you have any tires that are wearing oddly or does the truck pull to one side? You might have an alignment issue.

How is your heat? If you have a bad thermostat, the engine won't warm up and the computer will stay in open loop mode. This will really suck the fuel too. Check these and we can all get our heads together (BAM! Ouch! ) and see if we can figure out what your issue is. You will never get great mileage, but it does seem pretty poor.

 

Truck cruises very easily on the highway and does not lose speed when coasting.

Park brake lets go fully when released; the truck starts to roll as soon as the park brake is off.

And yes, I am in Canada, where we not only use the metic system to be different, but we also
use the Imperial system, with different size gallons. Just call us rebels :-)

Truck cruises arrow straight, even with hands off the wheel.

Heat is so intense, that even on cold days, I have to turn it down a few notches.
Engine temp gauge reads normal (middle position).

Thank you so much for your input and your suggestions!!! They are both welcome
and very much appreciated!

I will continue to monitor the truck every once in a while by taking my hands off the
wheel and letting it coast in neutral to check for drag/pull.

And although you did not suggest it, I believe that the engine is in good tune, as it
starts on the first turn of the key and runs very smoothly with no hesitation.

I think it is just the nature of the beast to be thirsty. Because winter grade gas is less
energy-intensive than summer grade gas, I shall probably have to wait for warmer
weather to see if conditions really improve.

Once again, many thanks for your valuable input and insight :-)
Sam

 

your L/100km are pretty much what I get with my 3rd gen. My 6L gmc was identical. my 4.8L gmc was marginally better.
https://www.fueleconomy.gov/feg/Find...n=sbs&id=31451
you have the rfe 6 speed trans. the 8 speed trans does get better mpg and doesn't run a power steering pump.
tips for improvement
-properly inflated tires
-get a tonneau cover; can add up to 1mpg. that is why all hybrid trucks come from factory with soft tops.
-do not drive with the tail gate down or removed...can loose up to 1mpg due to increased drag
-don't add suspension lifts or oversized tires

 

It sounds like you're getting about what you can. I pay a little extra to get pure gasoline in the winter. If they get up to 15% ethanol in your area, mileage will suffer. I'm several hundred miles farther south than you are so I don't deal with the winters like you get. Back in the 70's, I drover a truck in the northern tier of states and got some of what you get.

 

Thank you for your input, it is much appreciated!
I do keep my tires inflated to 40 psi.
I do have a tonneau cover.
I don't drive with the gate down.
The truck came with 20 inch wheels/tires, almost a monster truck :-)
Based on your experiences, I guess I shall have to live with the mileage.
I thought that this engine had a highway 8-to-4 cylinder feature, but I guess not.
Thanks again :-)
Sam

 

Your Truck does have the mds with 8-4 cylinders,, Only way to shut it off I believe is to have truck in tow/haul mode or with a programmer My 09 will run about 12-14 in dead cold of winters on highway. Dont trust what the computer says you are getting,,, do an actual test where you fill up and drive a few hundred kms and then refill and hand calculate it.. Even in all city driving i will get prob 300-400 kms to a tank, but then i also have the bigger 126 litre tank on both my trucks,,,,, my 15 has the 8 speed and it does get better mpg thats for sure

 

Wow, thank you ... to be fair, most of my driving is in the city, so at some point I will take a highway cruise to see how it goes.
I think that the mds only comes on above a certain speed? Once again, though, from all the feedback I am getting, it sounds
as if my mileage is about average.

One comment for you, though ... Even if you are getting 400 city km from a tank, and if your tank is 126 litres, then you are using
30+ litres per 100 kilometers! This translates to 8 miles per gallon!!! Does this not strike you as incredibly excessive?

I am grateful to you and to all of the others for the feedback that I am receiving. Thanks, everyone :-)
Sam