[MidWestEco]

2016 Eco 4x4 Crew 75k miles w/ GDE
In the Summer of 2017/2018 with most of my miles typically being a work commute of 21 miles each way I would routinely get 27+MPG. This year I struggle to get 25-25.5 and my Fuel App has showed a slow decline in total average fuel economy. My lifetime economy used to be 26.7 and through this year it's went down to 25.3 I know wind can be a killer but I've made several 1400 mile trips this year with an ATV and gear in the box I've only gotten about 21 on the interstate. Where last year I pulled a car trailer with a 3800 lb vehicle 600 miles and gotten 20mpg.

Basically what I'm trying to say is that I'm pretty sure it's more than just my mind Has anymore else experienced this? What can I check? Could a leaky/faulty injector cause it?

Thanks!

 

[MAS]

Personally I think its your mind. My truck is also GDE tuned. Pulling a 16 foot trailer with 4,000-4500 lb of building supplies got me 21 and change and part of that was with an empty trailer. The winter time will nock my mileage down 1-2 mpg and I live in South Texas.

You say a 3800 lb vehicle. How much does the ATV and gear weigh? To me wind means more than weight. I towed the 4000-45000 lb load and got over 20 mpg. Made the same trip a few weeks ago with a hunting stand on a trailer that weighted less than 2000 lbs but had a 5x5 flat front side and got 13 going into a head wind.

Another observation I have is that people tend to wear the new off things. My brother and dad both complained about their duramaxes loosing fuel mileage over years. I pointed out to them it looked like they drove them a lot harder than they did new, they paid attention to it and got their fuel mileage back.

 

[MAS]

I have seen the same drop off in my fuel mileage from driving habits. I use to almost always drive 60 mph commuting, now I know I can drive 70+ and still get killer fuel mileage for a pickup and find myself doing it more and more.

 

[MidWestEco]

I agree with the wind vs weight. If I'm going > 70mph with wind the MPG goes down dramatically. The ATV and gear probably weigh 800-900lbs and must create a decent amount of wind resistance vs a tonneau cover. Some of that is a side note and don't have too much issue with it. Though when I scroll back in my fuel app last year in the warmer months(In Nebraska) I was quite often getting 27+ on the work commute and now seems to be 2+MPG less nearly all the time. I know when I first got the Eco I would foot throttle through the gentle hills which probably helped but i don't think i did that last year at all. I still occasionally get what I consider a good MPG tank though. It might be partially in my mind, but I don't think completely.....though no issues with the truck really so maybe I just keep on truckin' and see what happens.

 

[justind]

Run some tanks with Diesel Extreme https://www.hotshotsecret.com/diesel-extreme/ additive and see if it improves. Many people swear by this stuff for all kinds of issues including worse fuel economy over time.

 

[Haul N Grass]

Try cleaning your MAP sensor..... Especially if you do not have a Tune ...

 

[MidWestEco]

Hot Shots Might be worth looking into or trying just to see....to this point I haven't used any additives.

 

[MAS]

Try cleaning your MAP sensor..... Especially if you do not have a Tune ...

Cant tell you how many times I have watched a video on how to clean it. I don't think ive ever seen one that shows where it is. They all just start with a dirty as hell MAP sensor in their hand. I probably need to clean mine, I never have.

 

[shaggn85]

Clean map, stanadyne fuel additive.

 

[tommyboy16]

This is my first post. 16' 1500 Eco sub 54,000 miles. Had the AEM done about a month ago and still waiting for my $$$. Paperword completed, notarized, and sent back. Mileage has gone down the toilet for what I believe to be multiple reasons. 1) Threw on a set of 275/65/20 Michelin 10 plys I got a sick deal on last fall. Better traction but I know, more rotating mass = less mileage. 2) Check engine light on since 45,000 miles PO4 code or whatever-low egr flow. Still came back after AEM-Dealer waiting for EGR cooler but have the valve and they are going to replace both when the cooler arrives. Asked them to clean the recirculation tube as well if not part of the program. Planned on buying a GDE hot tune with some of the settlement $$$ but found out that is a no go now. What are going to be my options after the egr system is replaced? I didn't get any referal information from GDE when they replied to my email. They just said the EPA killed their ability to perform any more tunes/ecu swaps. Appreciate any helpful input.

 

[TumaloKeith]

Change the air filter.

 

[BuffaloBill]

Has the fuel at your station changed from 100% petroleum to a bio-blend?

 

[MidWestEco]

I changed the air filter about 4 weeks ago, I haven't seen much of a difference, though it's also getting colder. The Fuel stations will also be changing now to #2 in this area, so it might be hard to compare with the combo of the Cooler Temps and Fuel change. I will look more closely to see if my regular stations have changed to a Bio Blend, though i've filled up several different places and seen lower MPG. Might be a good idea to take a look at the MAP sensor though. I will probably try some sort of Fuel Additive/Injector cleaner for Diesels. Being that I have no other issues besides a slight drop in economy just makes me a suspect injector(s) that aren't functioning optimally.
Thanks for Everyone's suggestions thus far.

 

[sourdo]

This is my first post. 16' 1500 Eco sub 54,000 miles. Had the AEM done about a month ago and still waiting for my $$$. Paperword completed, notarized, and sent back. Mileage has gone down the toilet for what I believe to be multiple reasons. 1) Threw on a set of 275/65/20 Michelin 10 plys I got a sick deal on last fall. Better traction but I know, more rotating mass = less mileage. 2) Check engine light on since 45,000 miles PO4 code or whatever-low egr flow. Still came back after AEM-Dealer waiting for EGR cooler but have the valve and they are going to replace both when the cooler arrives. Asked them to clean the recirculation tube as well if not part of the program. Planned on buying a GDE hot tune with some of the settlement $$$ but found out that is a no go now. What are going to be my options after the egr system is replaced? I didn't get any referal information from GDE when they replied to my email. They just said the EPA killed their ability to perform any more tunes/ecu swaps. Appreciate any helpful input.

Welcome!

I installed Cooper HT3 LT275/70R/17 E rated tires on my Eco. I expected by hear/say that I would lose mileage, but they hardly put a dent in my mileage. MAYBE 1 or 2 mpg less empty, none when towing. I use 65 psi in these tires, the ride is great. I can still get over 32 mpg on a good day.

Total bummer about GDE and glad to have my tune and the spare. I have over 32,000 miles on my 2017, 2/3rds of those miles are towing the RV. My last oil report was very, very good. I work this motor and make sure it gets hot in the winter. I also use Kleen diesel fuel additive.

Tune notwithstanding, my best suggestion is to make sure to get your truck up to temp in winter, though I don't know where you live. The way this engine introduces fuel for the DPF regeneration leaves fuel in the oil until it burns off. Short cold trips will kill this engine, or any other diesel for that matter. Plug in and use the front grill cover, or make some. The front cover makes all the difference in getting warmed up. Without it my truck won't get full hot in freezing temps, just bobble around 195 F. Stopping to idle for long periods drops my engine temp to 140 F. Cold blooded these diesels are.