[FaceDeAce]

You know, the truck is growing on me where I am getting to like it the more I drive it and work on it. However, the mileage really sucks. Appalling actually. My Ram with the 5.7 is way better and that isn’t saying a-lot because it isn’t great either, but it is a much bigger truck.

What types of things should I look into to tune out, repair/replace, to improve. My right foot isn’t that heavy. Something else must be going on. The truck runs great. Just that the gas gauge drops way too fast in a week of running around town to-fro work and errands.

2005 Dakota, ext cab, 4wd, 4.7 v8, auto

 

[FaceDeAce]

Things already done:
- cleaned throttle body and manifold inlet
- air filter replaced
- PCV system clean and clear including new valve
- spark plugs replaced
- EGR valve replaced

It is getting a front to back fluids changeout today, along with seal replacements and propeller CV replacement.

Anything other ideas, anything else I should look at while it is in the garage here?

 

[RXT]

You know, the truck is growing on me where I am getting to like it the more I drive it and work on it. However, the mileage really sucks. Appalling actually. My Ram with the 5.7 is way better and that isn’t saying a-lot because it isn’t great either, but it is a much bigger truck.

What types of things should I look into to tune out, repair/replace, to improve. My right foot isn’t that heavy. Something else must be going on. The truck runs great. Just that the gas gauge drops way too fast in a week of running around town to-fro work and errands.

2005 Dakota, ext cab, 4wd, 4.7 v8, auto

Start with actual fuel economy figures. It might seem like you're going thru more gas, compared to another truck, maybe because it has a smaller gas tank. Then do the usual stuff, like make sure the engine is in tune, not worn out or high mileage, tires are at proper pressure, fluids all topped up, etc.

you may find that fuel economy won't improve much. While the Dakota is physically smaller than a full-size, they are about the same weight. Your fuel economy won't really be any better than a full size.

Ed

 

[FaceDeAce]

The stops at the pump and hits to the visa confirm this

 

[RXT]

Computers are wonderful tools, but they aren't always accurate. For example, if you put even just one tire size larger on the truck, it throws off the computer and gives you a false answer. Start off by doing the math the old fashioned way and see if your figures confirms the accuracy of the computer. If they are identical, you'll know the computer wasn't lying. If the computer is way off…well you'll know you can't trust it. Also make sure the odometer is accurate too

Ed

 

[FaceDeAce]

Yup, been there done that on checks and considerations for tires, odo, etc. The math will not change these numbers more than .5 mpg. "The stops at the pump and hits to the visa confirm this".
These readings are also without reseting the console for 2 weeks, about 50 gallons of gas through it.

Are other owners getting same or in this range booting around town? On the highway if I keep the speed down, 50mph, on a straight and flat road, if I really gently milk it I manage to sip at 17-19mpg.

 

[~Raz~]

Maybe you should try driving without the trailer attached for a while....

 

[FaceDeAce]

LOL! yeah, see that is the thing. These numbers are with no load, nothing in the box, no trailer, and only one person it in. Just running into town and around for work, school, groceries, and odd/ends.

I have only trucks and SUV's, no cars. I know it is a truck, and what comes with that wrt economy. I am not comparing to any car or compacts or data sheets. I am comparing to my other full size trucks and SUV's driving the same roads. This one, the smallest of the fleet, is the worst on fuel by 20-30% yet has the smallest profile and engine. There must be some sensor or something out of whack. It runs great, it just seems to be a gluttonous pig about it.

 

[RXT]

Did you check the ATF? Low trans fluid will reduce economy….. How about O2 sensors?

Ed

 

[8cylinder287]

Clogged cats maybe? My cats were partially clogged, after fixing that issue I went from 13mpg on the highway to 21 if I'm gentle at 60mph, combined around 13 average, but that's with a lead foot.

 

[FaceDeAce]

I fail to see how atf would affect this. If the transmission is operating properly, shifting well, not hunting, not slipping. I just completed a complete fluids changeout. So if was that, it should be resolved now.

The cats, maybe. How do I know if they are clogged or not proper?

 

[FaceDeAce]

Just finished a 1200 mile round trip over christmas . Pretty much all freeway 60-75 mph, and fairly flat terrain. Running empty, no load. Although cool conditions -25 degC
Mileage; 13.7 mpg
( Disgusted, I would expect to see at least 17 out of a pickup in those conditions )

 

[~Raz~]

Just finished a 1200 mile round trip over christmas . Pretty much all freeway 60-75 mph, and fairly flat terrain. Running empty, no load. Although cool conditions -25 degC
Mileage; 13.7 mpg
( Disgusted, I would expect to see at least 17 out of a pickup in those conditions )

Thats about what my truck gets on the freeway too. My durango gets 11.
Maybe your truck isnt as broken as we thought.

 

[Rusty Boltz]

My 4.7 has a lifetime average of 19.3 (over 195,000 miles). I've never reset the computer. For the first 184k miles, I was driving it on the highway to work, (it got up to 19.7); lately, it's been around town. I did recently take a 600 mile trip at an average speed over 60mph with no change in average mpg. I can't imagine it ever getting as low as yours.

 

[FaceDeAce]

That's about the range of what I would expect to see out of this truck, Rusty. For some reason it isn't getting there, the gluttonous pig. So, wondering what to be looking at, checking, cleaning, clearing, replacing. ... ?

 

[Rusty Boltz]

That's about the range of what I would expect to see out of this truck, Rusty. For some reason it isn't getting there, the gluttonous pig. So, wondering what to be looking at, checking, cleaning, clearing, replacing. ... ?

I don't know what to tell you. The only thing that's ever been done to mine is routine maintenance.

 

[8cylinder287]

What sort of conditions are you driving in since you started noticing the poor mileage, the extreme cold (-35 Celsius here) has definitely put a dent in my mileage.

 

[Turbojeep]

Face, I get about the same milage as you do. I got 12.7 on this last fill up, 80% highway. Which seems to be about the average I get over the last 3 years I've had the truck.

I'd be happy with 15 and would kill for the high teens others claim.

 

[FaceDeAce]

What sort of conditions are you driving in since you started noticing the poor mileage, the extreme cold (-35 Celsius here) has definitely put a dent in my mileage.

It has been poor since I got it in June, 6 months ago. Seems to run in the 13-14 mpg range on the highway and 9-10 around town. This is 4wd with 4.7 and 5speed automatic 3.55 gearing 265/65R17 tires. Higher milers may be manual transmission or 2wd?

Wrt maintenance, I have done alot of repairs since I buying it. Fluids, tires, suspension, alignment, plugs, PCV, air filter, all usual neglected stuff and a few minor other things. Did this work not because of the mileage, because they needed attention. No mods done, all stock repair/replace parts and sizes.

Now I am focused on the mileage issue. Intake problem? Exhaust/Cat problems? Sensor problem? .... or is it just going to be a pig and that is all there is to it? I bought this half-of-a-half a-truck intending for it to be a more economic one-person runabout than my full size vehicles and leave the big ones parked for the more substantial usage. The reality is revealing the Dakota to be quite the opposite.

As comparison, my Ram 5.7 quad cab 4wd with half a load on gets consistently 18-19 highway and 15 town. The Ram also gets 12-14 pulling 6000lb trailer full of powertoys. My Chev 5.3 full size heavy 4wd SUV, Tahoe, full of passengers gets 17-18 highway and 15 town. For the little Dakota to be getting less on the highway running empty than those heavy weight comparisons get stomping around town .... and to accept that as "normal" is just insanely absurd, at least to me it is!

 

[Turbojeep]

That's what I planned on doing when I picked it up as well.... Logic would say that they should get at least similar milage. I thought it was due to a missfire code it had when I got it, but nothing I've done seems to change the milage.

I've thought about injectors,exhaust and the whole mess, but at this point I'm awfully temped to just find a 5.7 and get the 20-23 average everyone who does the swap claims.