MPG SUCKS!!!

[Hagar1]

I have a 2014 1500 Sport 5.7. Within the last 2 months by average MPG have gone from 11.5 to 9.5. Here within the last week it has gone to 8.6. I Mainly do city driving and haven't done anything differently. I haven't added anything to the truck, drive it the same as I always have, and same routes. Take kids to school, go to work, use q few times a week for work (not hauling anything), pick kids up and home. No check engine lights either. Curious if anybody else has ran into this issue or may possibly know of any causes I could start looking in to. Thanks in advance

I've been wrestling with a similar problem for almost 2 years. Everytime that I think that " I got it" I've been in for a disappointment. Everything that I have tried so far hasn't changed a thing. Re-torqued intake, Plugs, sensors, replaced PCM, brakes all around, all 4 oxygen sensors, throttle pedal, new spark plugs, compression test .... all the while,no codes.
The bottom line is nothing has changed. In the spring, I'm going to pull the underhood wiring harnesses apart and examine for corrosion at a splice.

 

[EdGs]

Is your coolant temperature accurate?

I had a 2001 Saturn that went from great gas mileage to crap, like from 30+ down to less than 20.

Talked with a tech, he said check the coolant temp sensor, said when they go bad, the car thinks the temp is super-cold and in return, dumps lots of fuel.

I also noticed my temp gauge needle was a bit lower at operating temp. Anyhow, replacing the sensor did the trick. Could be something similar with your Ram. Look into how to test the sensors for proper function.

 

[Daw14]

I forgot to mention brakes.

When the calipers, first drivers front started to seize it created a lot of heat. I tested the rotors with an infrared thermometer, this compares one side to the other to let you know there is a difference and problem.

I first noticed when the lieometer started reading less mileage than before.

Then a year or so later the same thing , mileage dropped plus I could smell the brakes were way hot. Was the passenger side.

Then about another year the rear starts to stick on one side , so now I have replaced all four calipers and rotors.

My mileage has returned to the previous normal.

 

[Hagar1]

Is your coolant temperature accurate?

I had a 2001 Saturn that went from great gas mileage to crap, like from 30+ down to less than 20.

Talked with a tech, he said check the coolant temp sensor, said when they go bad, the car thinks the temp is super-cold and in return, dumps lots of fuel.

I also noticed my temp gauge needle was a bit lower at operating temp. Anyhow, replacing the sensor did the trick. Could be something similar with your Ram. Look into how to test the sensors for proper function.

Interesting point! I've checked the coolant sensor against Intake air and Ambient, they are all very close when cold and appear to make logical changes when warming up as well as when hot. I think I might have a spare sensor on hand, I'll swap it out and see if anything changes.

 

[Daw14]

Apologies for the lack of details and I will go ahead and say that I have failed miserably regarding maintenance but really trying to get back on it.
I've had the truck for about 5 or 6 years now. Mileage is at 124,000. I've changed the air filter but it's been awhile. Haven't done the spark plugs (I know and I'm ready the **** I deserve lol). I've had to replace the bolts and have the manifold resurfaced 3 times now. O2 sensors replaced 2 years ago and no codes come up.
Complete honesty, I'm ignorant when it comes to working and maintenance on my truck besides oil changes. Any guidance as far stuff I need and should have done is greatly appreciated and I can always watch videos on how to do things.

Intake manifold 108 inch pounds , not the exhaust.

 

[zrock]

Well the first thing that come to mind is winter fuel you will always have a drop in the winter, next you said ball joints are shot so that is now creating your alignment to be out creating drag, check your brakes for a dragging brake, check wheel bearings i drove on a bad one for a year before i found it and it was so stiff i could not turn it by hand, check driveline for bad u joints. So if any of these are a issue you will loose fuel econ and if you have multiple happening well then that just increases the poor econ.

 

[Wild one]

One last thing. Truck has a horrible, loud, squeking noise. Does it going in reverse and driving, mainly over any kind of bump. I know my ball joints are shot. I have replacements and will be installed next week. Can't figure out where it's coming from though. Almost sounds like from the back springs. Hell, I don't know. Wheel bearings?

If the squeak is from the rear and the bushings /swaybar links etc. are all good,take a look at the rubber isolators on the top of the rear springs. My neighbour had issues with a squeak from the rear,it took me awhile to finally pin point it to the rubber isolators on the top of the rear springs being wore out.

 

[Racer9]

Not mentioned yet, fuel leak, look at fuel tank and lines for signs of leak, including at the top where the lines enter the tank.
Also injectors, so when you change plugs inspect them for rich or fouled looking.

 

[markabby]

And a can of Seafoam...

what does the seafoam do?

 

[EdGs]

Interesting point! I've checked the coolant sensor against Intake air and Ambient, they are all very close when cold and appear to make logical changes when warming up as well as when hot. I think I might have a spare sensor on hand, I'll swap it out and see if anything changes.

On my Saturn, when the sensor was bad, the needle was reading slightly over 1/4 with th car at operating temp. Normally the needle would be at 1/2 or slightly more on the gauge.

Don't remember how these sensors read, if voltage or ohms according to temp.

Also, could smell gas alot stronger.

Will be interesting to see if you find anything.

 

[Hagar1]

On my Saturn, when the sensor was bad, the needle was reading slightly over 1/4 with th car at operating temp. Normally the needle would be at 1/2 or slightly more on the gauge.

Don't remember how these sensors read, if voltage or ohms according to temp.

Also, could smell gas alot stronger.

Will be interesting to see if you find anything.

I am using an Ancel FX4000 code reader. It does a decent job of reading sensor values. As I said, it works OK BUT the support from Ancel borders on non-existant.
I'm going to dig out my MT 586 and see if I can get some resistance readings.
It is about -4C here today so the testing may wait a while.

 

[Hagar1]

On my Saturn, when the sensor was bad, the needle was reading slightly over 1/4 with th car at operating temp. Normally the needle would be at 1/2 or slightly more on the gauge.

Don't remember how these sensors read, if voltage or ohms according to temp.

Also, could smell gas alot stronger.

Will be interesting to see if you find anything.

If I recall correctly, they are an NTC thermistor, they are fed a 5 volt but output voltage varies depending upon the resistance cause by temp change.

 

[EdGs]

I am using an Ancel FX4000 code reader. It does a decent job of reading sensor values. As I said, it works OK BUT the support from Ancel borders on non-existant.
I'm going to dig out my MT 586 and see if I can get some resistance readings.
It is about -4C here today so the testing may wait a while.

Damn, that's cold. Glad I live in Florida.

 

[Hagar1]

Damn, that's cold. Glad I live in Florida.

Well , truth be told, it is unseasonably warm for the next few days. Couple of days back we had some -20C daytime temps that dropped to around -25C overnight.

 

[Daw14]

Damn, that's cold. Glad I live in Florida.

You and me both.

 

[Hagar1]

No big deal .......... we are a pretty resilient bunch up here Summers are beautiful, fishing and hunting are great. A 5 minute drive will put me into Boreal Forest with plenty of lakes and wild life.
No Gators, Pythons or other nasty creatures, only the odd Rattle Snake.
In the summer, it is fairly common to see Bears wandering around across the street. We see the odd Wolf and on occasion Coyotes. So, the area has its benefits. If I want a hot climate, I only need to wait 6 months.

 

[mands0807]

You and me both.

It's been cold enough here the past week...lows around 40F with 50% humidity is bone chilling

 

[crash68]

My power wagon gets down around there in the winter, but my half ton is always up around 15/16 in the winter,

My EcoD will get around 15/16 mpg, if I'm towing a travel trailer .. LOL

Mileage is at 124,000. I've changed the air filter but it's been awhile. Haven't done the spark plugs

When owners wonder about fuel economy, I say it's the spark plugs .. cause it has them(and missing a turbo).
Definitely gat all the vehicle maintenance up to date, including the spark plugs.

 

[wrench78]

I haven't seen anyone talk about the transmission. With that high of miles, maybe do for a transmission flush and filter change.

 

[Hagar1]

It's been cold enough here the past week...lows around 40F with 50% humidity is bone chilling

I remember being in Palo Alto CA a few years back. It was in mid-November. I flew from Winnipeg Manitoba wearing a light weight jacket. It was colder in Palo alto than it was in Winnipeg. Dress for the season but bring a sweater.