20% decline in MPG

[Cowpie]

On 5/9/2019 at 9:15 AM, TXGREEK said:

Just a thought, ethanol gas, sitting so long may have gunk up your fuel system? Try running a fuel system cleaner like “SeaFoam” and go from there.


Sent from above

Could be, but doubtful on the ethanol.  More likely the gasoline since it has varnishes and other stuff in it.

 

My 2500 runs on E85 fuel exclusively and has for 2 years. Same for our Equinox.   The 2500 will typically sit for weeks in my garage when we don't need it.  And it has never had an ethanol related fuel problem.  

 

But a fuel system cleaner could be a good thing.  With low use on the vehicle and depending on several other factors, the injectors could be not atomizing fuel properly if spray pattern is diminished.

[Mikey999]

On 05/05/2019 at 11:40 PM, Mikey999 said:

When i switched over to snow tires on other rims my mileage  dropped.  I will see what happens when i switch back in may.

 

And  now switched back to all seasons tires and rim and my original fuel economy is restored

[Chris Lieberman]

3 hours ago, Mikey999 said:

And  now switched back to all seasons tires and rim and my original fuel economy is restored

How much of a loss did you experience with the switch?

 

Thanks!

[Mikey999]

4 hours ago, Chris Lieberman said:

How much of a loss did you experience with the switch?

 

Thanks!

Now winter is colder but i noticed as soon as i switched  to the winter tires set fuel economy  dropped.  The all seasons i have are Michelin energy savers tires which have low rolling resistance and claim  to save 5 to 10% on fuel economy. They were on factory original  base rims 18inch. Switching  to winter its michelin xice2 on gm rims that are given on the off road package. I bought a winter tire package amd thats the rims they match with the tires . I suspect rims are heavier  but im not sure. On all seasons id get 10 to 11l per 100km  on highway and 15 to 16l per 100km in city . But on winter  tires is 11l  to 12 per hundred  on highway  and 17 to 20l per 100 in city. Thats going by what i read on the dashboard computer. 

[Chris Lieberman]

3 minutes ago, Mikey999 said:

Now winter is colder but i noticed as soon as i switched  to the winter tires set fuel economy  dropped.  The all seasons i have are Michelin energy savers tires which have low rolling resistance and claim  to save 5 to 10% on fuel economy. They were on factory original  base rims 18inch. Switching  to winter its michelin xice2 on gm rims that are given on the off road package. I bought a winter tire package amd thats the rims they match with the tires . I suspect rims are heavier  but im not sure. On all seasons id get 10 to 11l per 100km  on highway and 15 to 16l per 100km in city . But on winter  tires is 11l  to 12 per hundred  on highway  and 17 to 20l per 100 in city. Thats going by what i read on the dashboard computer. 

Ok thanks for the info. Mine seems to be slowly returning to normal, so far with no real explanation.

 

[Mikey999]

1 hour ago, Chris Lieberman said:

Ok thanks for the info. Mine seems to be slowly returning to normal, so far with no real explanation.

 

If its slowly returning to normal maybe they did reset  your ecm which means its learning your  driving style to save fuel