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Discussion Starter · #1 ·
I've owned this Durango for about a month or so and Ive done all the basics, new air filter, new spark plugs, oil change, cleaned throttle body, new wheels, an alignment, new wheel bearing.

I cannot figure out why the hell Im getting only 8.8 MPG. I had a code for enging running lean, and I had a code for Bank1Sensor2 heat circuit being out but I cleared it and they never came back.

What can I test or look for? 8.8mpg is atrocious, id be okay with even 12 average.
 

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What kind of driving do you do? Flat roads, hills, freeway, surface streets? Do you do a lot of idling? There are so many factors, if we are to help we need lots more details.

1949 International KB2, 302/T5
1968 Dodge Dart GTS, 340/727
2006 Dodge Magnum R/T "SRT Design"
2016 Dodge Durango Limited
 

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2016 Durango R/T Arizona
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Are you calculating this yourself or letting the car do it for you, if it has that display? The displays are never accurate.
 

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2 of the most common reasons are oxygen sensors and dirty fuel injectors.
1. You can try to clean the oxygen sensors...they can get plugged up with carbon/soot...and I might start there seeing you had a couple codes for them pop up in the past.
2. Run some good injector cleaner through the truck....or get an injector cleaning done...best option to quickly eliminate that.
I'd also verify tire pressures and that brakes aren't dragging.
 

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FYI, I found my on-board FE meter to read about 3 mpg happy. 2001 4.7L 2wd.
On flat highway at steady 74 I would average just over 19 mpg...city is probably closer to 12..especially with my heavy foot. If you drive with an egg under your foot you can get 15+ around town.
 

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Discussion Starter · #6 ·
I mostly drive in a small town or on highways. Its winter so it gets idled a lot, but it goes through gas like a motherfer and I can never keep a tank for very long. The instant MPG on the display says 9 at 65mph with cruise control
What kind of driving do you do? Flat roads, hills, freeway, surface streets? Do you do a lot of idling? There are so many factors, if we are to help we need lots more details.

1949 International KB2, 302/T5
1968 Dodge Dart GTS, 340/727
2006 Dodge Magnum R/T "SRT Design"
2016 Dodge Durango Limited
 

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Discussion Starter · #7 ·
2 of the most common reasons are oxygen sensors and dirty fuel injectors.
1. You can try to clean the oxygen sensors...they can get plugged up with carbon/soot...and I might start there seeing you had a couple codes for them pop up in the past.
2. Run some good injector cleaner through the truck....or get an injector cleaning done...best option to quickly eliminate that.
I'd also verify tire pressures and that brakes aren't dragging.
Ill take a look at the o2 sensors. Do i have to replace all four, or just the top two? I think the downstream O2 sensors dont get used to calculate the fuel mixture, but I could be wrong.
I put a shitload of marvel mystery oil in when i first got it, and after a few tanks worth I put in a shitload of seafoam. Might have to take a look ay the fuel injectors
 

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Discussion Starter · #8 ·
Are you calculating this yourself or letting the car do it for you, if it has that display? The displays are never accurate.
I just used the display, but it seems pretty accurate to me because the thing goes through fuel like its nothing. I dont even drive that far or for long periods.
 

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Replace all of your O2 sensors, well worth the cost and effort.
 
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I mostly drive in a small town or on highways. Its winter so it gets idled a lot, but it goes through gas like a motherfer and I can never keep a tank for very long. The instant MPG on the display says 9 at 65mph with cruise control
Nothing sucks gas mileage down like idling. Not saying you don't have other issues (as stated, since you had those o2 codes, I'd check the upstream ones) but idling is brutal for the mileage.

1949 International KB2, 302/T5
1968 Dodge Dart GTS, 340/727
2006 Dodge Magnum R/T "SRT Design"
2016 Dodge Durango Limited
 

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2016 Durango R/T Arizona
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You first need to manually calculate the mileage and be sure you always fill the tank to the same level, such as when the pump clicks off. You'll need to do one tank from scratch and record your beginning mileage. The second tank will be what you start doing the subsequent math on.
 

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Ill take a look at the o2 sensors. Do i have to replace all four, or just the top two? I think the downstream O2 sensors dont get used to calculate the fuel mixture, but I could be wrong.
I put a shitload of marvel mystery oil in when i first got it, and after a few tanks worth I put in a shitload of seafoam. Might have to take a look ay the fuel injectors
You have 4?
Must be a California spec Durango.
Yes, with all those additives they probably got plugged or damaged.
BTW, don't use a cheap China brand...use a good OEM brand such as Denso or NTK.
Should find them on Rockauto.com and they have a discount code in the vendor section to use.
 

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Discussion Starter · #13 ·
You have 4?
Must be a California spec Durango.
Yes, with all those additives they probably got plugged or damaged.
BTW, don't use a cheap China brand...use a good OEM brand such as Denso or NTK.
Should find them on Rockauto.com and they have a discount code in the vendor section to use.
I actually only have two. My mistake lol.
also. I tried to replace the rear one and it wouldn't come out no matter what I did. I used a 7/8" o2 sensor socket andI couldnt get the rachet in there at all.
idk how the hell someone would get it out without dropping the whole exhaust.
i unplugged it so it the computer wouldnt read it incorrectly and i think im getting better mpg, but could be placebo
 

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I seem to remember a bypass harness available aftermarket you could plug in...then you could remove the Cat to gain some mpg and 10hp...might be plugged too.
I've never replaced mine...so can't say I know how difficult it is...maybe a crows foot socket will work?
 
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