4.7L owners I would like to know how you are doing in regards to MPG

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tdela

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I have an 03 4.7 with 120k miles

19-20 highway mpg and 14-15 in town

Had issues with gas mileage right after I hit 100k
changed plugs and O2 sensors and it went back up after that
 

dRAMbuie

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Hi. I don't know about miles about gallon or litres per 100 km. But my truck costs about 110$ to fill. In the city that'll get me 400 km. On the hiway I have hit 550 km. I think its a pig on gas.

Stan.
Posting in kms I'm assuming you're in Canada.
At an estimated fuel price of $1.25/liter that means you're using about 88 liters over 400km.
So... 22L/100km which is about 11mpg.

Which is absolutely horrendous.
That's what I get pulling 6500lbs of trailer.

What year and eng/tran/gear configuration do you have?
I know the older models didn't get anywhere near the mileage the new ones get but your case seems extreme.

Either that or the Hemi is much more fuel efficient than the 4.7L
 
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xb1230

xb1230

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I have a 35 gallon tank and the gas price around here is 1.49$/Liter...

That is over 150$CAN to fill the truck.

I am running at 10.5MPG... I just switched the tires on the truck (Had 275/70 R17, swapped with 235/75 R17) hoping that it will ease it up on the gas.

2 days since the tire swap and the first thing I can say is the truck behaves so much better with the new tires that even if doesn't change anything in regards to MPG, the swap was well worth it.

I am currently running a tank with Fuel System Cleaner and will proceed to change the Spark Plugs next week, and might also give a go to swap the O2 sensors.

I drive very softly grandpa like and would like to be getting just shy of 15MPG, which is what many here have stated they can do. I'm being really soft on accelerations and don't go over 2k rpm, heck I even let go of the gas so the tranny will shift at 2k rpm.
Only time I step on it a little more is when I get on the highway, just want to move up to speed fast enough to not anoy other folks driving at speed.

I have already given the TB a nice clean, and it helped the Idle smoothness, and with the new tires I have a better smoother and a little more vigourus accel but nothing to write home about, which is why I'm thinking of moving to the O2 sensors and also resetting the PCM/TCM to re-init the learning mode to my driving habits.

Being from Canada we are heading towards the fall and temps are slowly going down so nothing to help improve MPGs.

Since I am getting the diesel ticking in the Morning when the engine is stone cold, I am thinking of doing a good Engine oil system flush to make sure I get rid of any sludge in the upper engine part.
There is a possibility I will store the truck for the Winter so I could also get the engine out while stored and do a little bit of work on it during the winter.
 
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xb1230

xb1230

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Just thought I would post an update to this thread.

After some TLC on the engine and surroundings, a can of Royal Purple Injector cleaner to half of a tank of gas and smaller 235/65/17 meat on the rims, I am sitting a little lower in Fuel Economy.

City 21.5L/100km (10.9 MPG)
Highway 12L/100km (19 MPG)

For an average of 18.1L/100km (13 MPG) from the DTC, 19L/100km (12.4 MPG) calculated.

Better but still extremely high considering I drive the darn thing like a 95 year old man...
Looking forward to see if the following tanks will even improve over this.

Over the weekend I will be swapping the Spark Plugs as well as redoing the grounds from the chassis to the Engine and probably gonna go for Big 3 type of job. I would hope this would help the sensors get a better reading and maybe help with fuel economy.

If they come in before the weekend I'll also be swapping the O2 sensors which could make a huge difference as well.

Stay tuned. (Pun intended...)
 
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xb1230

xb1230

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Wanted to add that even though the difference seems minor, My cost of running the truck from a fuel standpoint has gone from 31$/100km(62 miles) down to 25$/100km(62Miles).

Pretty significant difference on the long term.
 

regularcab2500

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those old 4.7s get gummed up really bad too..try and cycle some seafoam through it every few fill ups to clean it out maybe..i dumped my 2010 4.7 because it got 13mpg average which is what i get in my 3/4 ton with a 6.4

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90guy

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My 06 4.7 was making around 12mpg in the city and roughly 14.6 on the highway. But that is mostly at 70-80 mph depending on the interstate and the hills I was driving through. Got sick of it being not that great for mileage.
 

regularcab2500

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i think they should have focused on the fuel economy of this motor more because its a better motor than the 3.6 imo and had it done better in fuel efficiency it probably wouldnt have been replaced by the 6cyl. much better base model motor me thinks

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xb1230

xb1230

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As far as I can tell (correct me if I'm wrong anyone), but the 3.6L is a derivative of the 4.7L with 2 less cylinder... so they sort of did improve the fuel economy of the V8 in removing those 2 pistons and surroundings... ;)
 
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xb1230

xb1230

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At this time the spark plugs are what has provided the best improvements in both performance and MPG.

I am up 1 Miles per gallon in all circumstances... not a major improvement but I am considering all of them.
 

regularcab2500

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As far as I can tell (correct me if I'm wrong anyone), but the 3.6L is a derivative of the 4.7L with 2 less cylinder... so they sort of did improve the fuel economy of the V8 in removing those 2 pistons and surroundings... ;)

no the old 3.7 they had was an LA block that was based directly on the 4.7...it was junk in a pickup truck but then again all motors from 10 years ago are pretty much junk in comparison..the 3.6 pentastar is a pentastar motor which i believe they used in the mitsu****sis they called chryslers from the 80s (didnt fact check that last part too lazy :p)

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regularcab2500

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no thats the ecodiesel..yes it is 3.6L but it is actually a maserati engine

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hemihustlin

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Pretty sure the 3.6 pentastar is an all new chrysler original design. Good read about it on allpar.
 

regularcab2500

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yeah i get 12mpg in my 6.4 hemi 3/4 ton (3.73gears, no mods) so if youre below 10 in a half ton you need to lay off the gas or your truck is broken!

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xb1230

xb1230

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I get about 14.5 to 16 avg depending on how hard I punch it.

5.7 hemi, 3.55 gears, 4x4

Your 3.55 gear ration does provide a lot of help. I can't see my big ass heavy honk of metal move well with lower than 3.92 in the rear end with the anaemic 4.7L I have.

Also on the Pentastar engines here is some good reading :Pentastars - advanced V6 engines from Chrysler (and Mercedes)

Also they have some nice info on the new "Ferrari-Maserati" derived V6 which I a little different and more costly than it's genetic parent the 3.6L...

For some reason I had associated the "Pentastar" with the "Volvo Penta" marine diesel engine, which is why I thought the Pentastar engine was the Eco-diesel. My bad.
 

LS5DodgeRam

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I have a 2wd you inch lifted and 35x12.50 s on my 4.7l with 3.55 gear and I get 9.5 mpg average
 

Egress

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I found the previous owner of my truck, his story is that he loved my truck with every ounce of his heart but couldn’t justify the 4.7 power/mpg with a Hemi engine that has more power/mpg in the later models.

I can understand 100%, but since I will have the truck paid off in 3 months I can’t complain. I will keep driving and loving her until it’s time to trade up to a Cummins.

Aside from the 3rd gen styling, I have had a lot of people amazed when I tell them it’s an 03. Still runs strong and sounds good, yeah it’s not the best on fuel but then again I'm not driving a car.
 

MarkV

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I found the previous owner of my truck, his story is that he loved my truck with every ounce of his heart but couldn’t justify the 4.7 power/mpg with a Hemi engine that has more power/mpg in the later models.

I can understand 100%, but since I will have the truck paid off in 3 months I can’t complain. I will keep driving and loving her until it’s time to trade up to a Cummins.

Aside from the 3rd gen styling, I have had a lot of people amazed when I tell them it’s an 03. Still runs strong and sounds good, yeah it’s not the best on fuel but then again I'm not driving a car.

Same thing here. Getting a average on 15-16mpg (14.7 L/100km). Mostly highway and a little city in there. I do have a Edge CS in it. I think that is the difference.
 
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