Fuel economy questions?

[rosco11]

Fellas,

I have a 2015 ram bighorn with a 5.7 L hemi. We have been towing a small 5 x 10 enclosed utility trailer for the past couple of years. we have made numerous trips between Long Island and the West Coast of Florida.

I always have this thing switched to “tow/haul” mode. And whenever we are trailing, I’m only using premium fuel.

For some reason, we are averaging 13.5 miles per gallon for the first 2/3 of the journey. Then the last 350 miles or thereabouts, the fuel economy starts crashing. And it doesn’t matter which direction we are driving. By the time we get to Florida or Long Island it winds up averaging around 12.1 miles per gallon to 12.3 miles per gallon.
By the way I have routinely changed the transmission fluid and have the new PPE pan, I have changed the transfer case fluids, front and rear differential fluids. I am using the “ high-performance lubricants” motor oil for the past 20,000 or so. And I have routinely changed the air filter. The only thing I haven’t changed so far all the spark plugs. And I’m about 125,000 miles on the truck.

And I can’t figure out why fuel economy seems to be crashing for the last 350 miles of the journey. Once again, it doesn’t matter which direction we are going. It will average 13.5 miles per gallon for most of the journey. Then when we get to our destinations, it’s somewhere around 12 miles per gallon to 12.3 miles per gallon.

I’m looking for explanations on why this could be happening?

Thanks!

Tow/hual mode will hold it in gear to a higher RPM and depending on the load may keep it from going into overdrive. So, yes, your 6000lb truck towing a 3000lb trailer is going to get the suck for gas millage. 12 to 13.5 could be hills, heat, lower speeds, even wind. absolutely nothing to worry about. It is still not bad for pushing 8000lbs down the road at highway speeds. One of the big reasons people opt for the 2500 series is because with more power, and more towing capacity it does not get any worse millage when towing stuff. If you drag stuff around reguarly, think about upgrading to a 2500. If not, relax, dont worry. You are still getting city millage on the highway with 8000lbs of metal.

 

[TC Retired]

Suggest using copper Anti-Seize on the threads. These long change interval plugs are in for a long time. Making sure to NOT get any on the electrodes...

 

[fitzdicksn]

Fellas,

I have a 2015 ram bighorn with a 5.7 L hemi. We have been towing a small 5 x 10 enclosed utility trailer for the past couple of years. we have made numerous trips between Long Island and the West Coast of Florida.

I always have this thing switched to “tow/haul” mode. And whenever we are trailing, I’m only using premium fuel.

For some reason, we are averaging 13.5 miles per gallon for the first 2/3 of the journey. Then the last 350 miles or thereabouts, the fuel economy starts crashing. And it doesn’t matter which direction we are driving. By the time we get to Florida or Long Island it winds up averaging around 12.1 miles per gallon to 12.3 miles per gallon.
By the way I have routinely changed the transmission fluid and have the new PPE pan, I have changed the transfer case fluids, front and rear differential fluids. I am using the “ high-performance lubricants” motor oil for the past 20,000 or so. And I have routinely changed the air filter. The only thing I haven’t changed so far all the spark plugs. And I’m about 125,000 miles on the truck.

And I can’t figure out why fuel economy seems to be crashing for the last 350 miles of the journey. Once again, it doesn’t matter which direction we are going. It will average 13.5 miles per gallon for most of the journey. Then when we get to our destinations, it’s somewhere around 12 miles per gallon to 12.3 miles per gallon.

I’m looking for explanations on why this could be happening?

Thanks!

DO you reset the mileage computer before you start the trip? if not, the computer will display the mileage from running around without the trailer. As you put more trailer tow miles on during th trip, the fuel economy displayed will gradually drop. This because the mileage displayed is not an instant mileage calculation. It is an average over say the last 200-300 kms. Other factors are things like even a slight change in grade which may not be notuceable, a slight tail wind ie which way are the prevailing winds relative to your trip.

 

[IdahoDen]

Fellas,

I have a 2015 ram bighorn with a 5.7 L hemi. We have been towing a small 5 x 10 enclosed utility trailer for the past couple of years. we have made numerous trips between Long Island and the West Coast of Florida.

I always have this thing switched to “tow/haul” mode. And whenever we are trailing, I’m only using premium fuel.

For some reason, we are averaging 13.5 miles per gallon for the first 2/3 of the journey. Then the last 350 miles or thereabouts, the fuel economy starts crashing. And it doesn’t matter which direction we are driving. By the time we get to Florida or Long Island it winds up averaging around 12.1 miles per gallon to 12.3 miles per gallon.
By the way I have routinely changed the transmission fluid and have the new PPE pan, I have changed the transfer case fluids, front and rear differential fluids. I am using the “ high-performance lubricants” motor oil for the past 20,000 or so. And I have routinely changed the air filter. The only thing I haven’t changed so far all the spark plugs. And I’m about 125,000 miles on the truck.

And I can’t figure out why fuel economy seems to be crashing for the last 350 miles of the journey. Once again, it doesn’t matter which direction we are going. It will average 13.5 miles per gallon for most of the journey. Then when we get to our destinations, it’s somewhere around 12 miles per gallon to 12.3 miles per gallon.

I’m looking for explanations on why this could be happening?

Thanks!

I had a new 2013 5.7 L 1500 for nine years and averaged about 17.5 MPG without towing with average about 14 MPG towing our 10 foot utility trailer. So the big question is how heavy of a load do you have in that 5 x 10' trailer?
Next question is are you calculating that mileage yourself are you going by what the dash tells you?

My guess, without answers to those two questions, is it is being affected by congestion and speed limits during the various parts of the trip. But to be honest with you, I've never had anybody call a one MPG difference "crashing".

 

[Hardracer]

I'm gonna add also...
Your getting 12-13mpg with a trailer your doing pretty darn good id say.The cruise control does help on those long runs and going through lower Geogria definitely sucks for speeding..
Im 12-13mpg without a trailer go figure...lol
I'm gonna throw some fuel on the fire here about the octane subject...MIne calls for mid grade but I'll swear to everyone here it runs like crap on 89 compared to the higher stuff 93...I can't explain it.
Next thing for the OP..
If you have an Advance Auto up there or even down here somewhere(there here in fla)when you change the plugs...AA will price match(rock auto in this case)if that store has the item in store and doesnt have to order it..saved me a ton(like half)when I did my plugs.i hope they still offer that deal.
Get the magnetic socket also as Ramdiver suggested,so much nicer for the job.most auto stores have that on the shelf.
I also agree with F350 about how the computer displaying is calculated through a run(a tank).I seem to recall reading something about that with Ford a few back if I remember right(I read way to much to remember it all).
Course this forum doesn't help with all this dern knowledge from these fine folks here..just can't thank you guys enough for this stuff that is just really old school knowledge...books don't tell us these kind of tidbits.

 

[Tom Davis]

If you are getting 12-13 with a trailer don't complain. I get 12.5 on average without.

 

[HangmanNY]

DO you reset the mileage computer before you start the trip? if not, the computer will display the mileage from running around without the trailer. As you put more trailer tow miles on during th trip, the fuel economy displayed will gradually drop. This because the mileage displayed is not an instant mileage calculation. It is an average over say the last 200-300 kms. Other factors are things like even a slight change in grade which may not be notuceable, a slight tail wind ie which way are the prevailing winds relative to your trip.

I always reset the trip meter before every trip. Our journeys around 1200 miles.

On the next trip down, I’m going to do the math with the total number of gallons burned versus the miles traveled

I also plan on changing the spark plugs and cleaning out the throttle body And probably clean out the O2 sensor

Thanks for all the help!

We’ve been busy packing to escape the ********* peoples Republic of New York State!

 

[Zoe Saldana]

Fellas,

I have a 2015 ram bighorn with a 5.7 L hemi. We have been towing a small 5 x 10 enclosed utility trailer for the past couple of years. we have made numerous trips between Long Island and the West Coast of Florida.

I always have this thing switched to “tow/haul” mode. And whenever we are trailing, I’m only using premium fuel.

For some reason, we are averaging 13.5 miles per gallon for the first 2/3 of the journey. Then the last 350 miles or thereabouts, the fuel economy starts crashing. And it doesn’t matter which direction we are driving. By the time we get to Florida or Long Island it winds up averaging around 12.1 miles per gallon to 12.3 miles per gallon.
By the way I have routinely changed the transmission fluid and have the new PPE pan, I have changed the transfer case fluids, front and rear differential fluids. I am using the “ high-performance lubricants” motor oil for the past 20,000 or so. And I have routinely changed the air filter. The only thing I haven’t changed so far all the spark plugs. And I’m about 125,000 miles on the truck.

And I can’t figure out why fuel economy seems to be crashing for the last 350 miles of the journey. Once again, it doesn’t matter which direction we are going. It will average 13.5 miles per gallon for most of the journey. Then when we get to our destinations, it’s somewhere around 12 miles per gallon to 12.3 miles per gallon.

I’m looking for explanations on why this could be happening?

Thanks!

Try 'Cataclean' a dirty converter can harm mpg under various conditions

 

[Hagar1]

Don't waste your time or money on the O2 sensors on Amazon, they are pure Chineseium and pure garbage. The sensors are hard enough to change, without doing them twice.
The other thing is the sparkplug, I completely agree with others on the OEM plugs. The other thing ...... COPPER Antisieze, the nickle based stuff will give you problems down the road. I put nickle antifreeze on my airplane sparkplug and learned a very hard and expensive lesson. Nickle based stuff is good but just not for spark plugs

 

[Govtman]

And, don't forget the game-changing, 'must have', magnetic swivel spark plug socket.

There's usually a similar product on both Amazon.com & Amazon. ca .

https://www.amazon.ca/gp/product/B0014ZVSVK/ref=ox_sc_saved_title_1?smid=A3DWYIK6Y9EEQB&th=1

.

Worth restating!

Oh and going after those back driver plugs, you will be climbing up on engine bay so good padded towels etc to put on radiator core support to save the knees!!!

 

[Hardracer]

[QUOTE="HangmanNY,
We’ve been busy packing to escape the ********* peoples Republic of New York State!
[/QUOTE]

I hate to say this Hangman.....but my state of Fla.for some 50years in my opinion has been changing on the political votes is that the northern majority coming here has been going in the wrong direction since the northern invasion.....I hope your not in those beliefs from up there.i can see it now..higher taxes,beliefs from the northern communities and whatnot.it takes its toll on the voting committees eventually(and has been changing)... I'm probably gonna leave my life state in the next 10 years because of it.
If your not to far away I'll come give ya a hand changing the plugs....no beef about that.id love to lend a helping hand over a few brews and mixed drinks...lol
Oh boy fellas I was almost close to a rant again...my apologies...lol

 

[HangmanNY]

[QUOTE="HangmanNY,
We’ve been busy packing to escape the ********* peoples Republic of New York State!

I hate to say this Hangman.....but my state of Fla.for some 50years in my opinion has been changing on the political votes is that the northern majority coming here has been going in the wrong direction since the northern invasion.....I hope your not in those beliefs from up there.i can see it now..higher taxes,beliefs from the northern communities and whatnot.it takes its toll on the voting committees eventually(and has been changing)... I'm probably gonna leave my life state in the next 10 years because of it.
If your not to far away I'll come give ya a hand changing the plugs....no beef about that.id love to lend a helping hand over a few brews and mixed drinks...lol
Oh boy fellas I was almost close to a rant again...my apologies...lol
[/QUOTE]

We are very conservative. we might be Yankees but we’re NOT damn Yankees!

I just ordered that 5/8” magnetic swivel spark plug socket.

 

[demonram]

I watched a couple of YouTube videos on how to change the plugs. I don’t want to do it frequently. I’m assuming the NGK iridium plugs are good. Should be good for about 100,000 miles. Have you guys had good results with those plugs?

I put iridium plugs in mine at about 92,000 miles, and now with 168,000, truck still runs great. The local NAPA dealer told me to put them in it and I would never have to change them again. Don't know if I would go that far, but they seem to be doing good.

 

[HangmanNY]

Try 'Cataclean' a dirty converter can harm mpg under various conditions

So even if I don’t have any current “codes” are you saying that it is good for “preventative maintenance/cleaning”?

 

[Zoe Saldana]

Yes, I did it and noticed a mpg improvement. I have 89K miles.

So even if I don’t have any current “codes” are you saying that it is good for “preventative maintenance/cleaning”?

 

[Hagar1]

Worth restating!

Oh and going after those back driver plugs, you will be climbing up on engine bay so good padded towels etc to put on radiator core support to save the knees!!!

Those plugs are easy, just jack up the driver side, pull the wheel and the fender liner and they become very nice to work on.
The ugly one was the passenger side rear ..... #8, it is a real PIA.

 

[Hagar1]

Those plugs are easy, just jack up the driver side, pull the wheel and the fender liner and they become very nice to work on.
The ugly one was the passenger side rear ..... #8, it is a real PIA.

Sort of like doing plugs on a Chrysler back in the 1970s ...... most from the top but the driver side rear, you needed a hoist. Yes, #5&7 were nasty.

 

[04fxdwgi]

Sort of like doing plugs on a Chrysler back in the 1970s ...... most from the top but the driver side rear, you needed a hoist. Yes, #5&7 were nasty.

Brake lines, booster and steering intermediate shaft made it awkward, but never needed a lift to do plugs on any of the 318, 340,383, 440 or 426 engines (admit the 426's were the easiest for obvious reasons) I had or worked on in the 70's / 80's.

 

[2003F350]

Those plugs are easy, just jack up the driver side, pull the wheel and the fender liner and they become very nice to work on.
The ugly one was the passenger side rear ..... #8, it is a real PIA.

I've had far too many vehicles that were hard to do plugs on. The worst I owned was a '99 S-series Jimmy with the 4.3, the center plug on the driver's side (#3 IIRC) was almost impossible to get at because the steering shaft was about 3/4" off the boot for the plug. Had to slide a spark plug socket on it, then use an offset wrench to get it out...all through the fender well because that was the easiest way to get to it.

 

[Hagar1]

Brake lines, booster and steering intermediate shaft made it awkward, but never needed a lift to do plugs on any of the 318, 340,383, 440 or 426 engines (admit the 426's were the easiest for obvious reasons) I had or worked on in the 70's / 80's.

It was a lot easier to access those back 2 on drivers side. Yes, you could get them all from the top alright but your hands might come out as hamburger. Then there was the hot manifolds from driving from Toronto to Ottawa in the summer. No, from the bottom was my go to.