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Discussion Starter #1
I bought my 2014 Eco manual at the end of January and I have 5500 miles on it now. I previously owned a 2011 Eco manual and it was great.

My issue with my 2014:

Lets say im driving at 70 mph and will set the cruise control while on the highway at 70mph and the instantaneous mpg will flash on the dashboard. For example before I set it to cruise control lets say my average [could be 25, 50 or 500 mile average] was 40 mpg.

Sometimes when I set it to cruise the instantaneous mpg will flash 90% of the time a number over 40 mpg but on the mpg average will start to drop like a rock. I'm no math wiz but I know that if you are getting instantaneous numbers that are over your average your average should not drop, it should stay the same or increase.

Once I notice this happening I will turn cruise control off completely, pull the car out of gear for a second, put it back in gear and then back on cruise control and back at 70mph on cruise and the number will start to act normal again.

I don't understand why this happens. It's like the computer program that doesn't mpg is messed up. This doesn't happen all the time but enough that I notice it and it doesn't make me very happy.

Has anybody else had this issue? I haven't called the dealership yet because I wanted to do a little research on my own.

I hope what I posted made sense. It was kind of hard for me to explain :uhh:

Thanks!
 

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I bought my 2014 Eco manual at the end of January and I have 5500 miles on it now. I previously owned a 2011 Eco manual and it was great.

My issue with my 2014:

Lets say im driving at 70 mph and will set the cruise control while on the highway at 70mph and the instantaneous mpg will flash on the dashboard. For example before I set it to cruise control lets say my average [could be 25, 50 or 500 mile average] was 40 mpg.

Sometimes when I set it to cruise the instantaneous mpg will flash 90% of the time a number over 40 mpg but on the mpg average will start to drop like a rock. I'm no math wiz but I know that if you are getting instantaneous numbers that are over your average your average should not drop, it should stay the same or increase.

Once I notice this happening I will turn cruise control off completely, pull the car out of gear for a second, put it back in gear and then back on cruise control and back at 70mph on cruise and the number will start to act normal again.

I don't understand why this happens. It's like the computer program that doesn't mpg is messed up. This doesn't happen all the time but enough that I notice it and it doesn't make me very happy.

Has anybody else had this issue? I haven't called the dealership yet because I wanted to do a little research on my own.

I hope what I posted made sense. It was kind of hard for me to explain :uhh:

Thanks!
Although I'm not an expert in vehicle diagnosis, the dealership would be a good suggestion to look into this further. However, I would be happy to reach out to them on your behalf! Feel free to send me a private message along with your VIN, current mileage, contact information and preferred dealership. Looking forward to hearing more about this!

Patsy G
Chevrolet Customer Care
 

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Does the Eco show the miles traveled for the same average? For the average MPG to "drop like a rock", it would seem that the miles are not being added correctly.
 

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Does the Eco show the miles traveled for the same average? For the average MPG to "drop like a rock", it would seem that the miles are not being added correctly.
No, My Eco game could say 36 mpg for 25 miles traveled but 29.9 in the same 25 trip 1 miles.

The MPG game literally counts down at idle.
 

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The MPG game literally counts down at idle.
I've seen my trip do the same.

Ok, I can think of two ways to do an average:
1) Record the millage traveled and gallons used. Re-calculate the average from the updated totals. That's probably what the trip is doing.
2) Record the miles traveled for each unit of fuel used. Store each unit in it's own memory location so you can drop off older units as they "expire". That's probably what the eco game is doing. It's the only way you can do a average of an average (which is what MPG is) - by averaging in measurements of equal quantities of fuel. (You can't average MPG over same number of miles - it doesn't work.)

But I can see how the eco game could be going down when the instantaneous MPG is higher than the average - due to the "expiring" of an even higher MPG. Perhaps 25 miles ago the car was going downhill with sky high MPG (>99 MPG). But that's now expiring, causing the 25 mile average to drop.

I'm not sure why trip and game readouts would differ for the same miles traveled. It suggests that one of them is totaling wrong - or at least differently.

Update: I read the manual for my year. It didn't give me a clear picture of just how that eco display works. But it does seem to be aimed at driving habits, so I'm wondering if it's subtracting some 'effects' out of it.
 

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The ECO game display in my car tends to be more accurate than the trip odometers. To diagnose this you need to reset a trip odometer when you turn your cruze control on and then drive for 25 miles. Check the two displays. They should be within 1 MPG of each other. The game display appears to compute MPG from a different set of numbers than the trip odometers.
 

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Discussion Starter #7
Thanks for the responses. It happens in the 25/50/500 variety of the mpg game.

I just don't get how pulling it out of gear and turning off cruise and then putting it back in gear and re - initializing cruise at the same speed fixes it and the mpg average starts to go back to where it should be.

Same grade and quality of road, same weather, same rpm and speed

:question:
 

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Discussion Starter #8
Personally I like the way the Eco game was set up in the 2011 Cruze Eco I owned.

It was a little more basic, but at least it didn't malfunction!
 

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I've never had any issues on my 2014 Cruze 6MT. Remember that the computer looks at 25/50/500 mile blocks to get that average. So for example say you have it set to show a 25 mile average.

Currently lets say you have an average MPG of 35 calculated from various MPGs for all 25 miles.

As you drive you add more current MPG values, but older values continue to fall off and no longer count towards the average. If you had a period of very good fuel mileage, say 5-6 miles of 60 MPG, eventually that data will fall off once it gets pushed back. This means that even though your average is 35 MPG, and you are currently getting 50MPG, as those 60 MPG values fall off your AVERAGE MPG will actually go down even though you are currently getting a higher MPG.

Does that make sense? Sounds like you are just turning it on as higher averages are falling off the further you drive. Obviously if it continues to fall and never goes back up that is a problem. But I've never seen that happen for me. I do get it where the Average drops even though my current MPG is higher.
 

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Thanks Ajn, makes sense.

I drove home from Kalamazoo to Ann Arbor Michigan last Friday which is a 2 hour drive, my first big trip east with my summer wheels and tires on the car in good weather. I was in cruise at 70 mph for almost the whole trip and at one point I hit 49.5 mpg on the 25 mile average, and 47.7 on the 50 mile average. Best milage yet since I've owned it but I've bad my winter setup on the car since the day after I bought it!
 

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Nice! I had an average of 59.7 on the 25 mile trip on a long downhill section coming back to Phoenix from LA. Was nice even though I know most of it was the downhill haha.
 

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Personally I like the way the Eco game was set up in the 2011 Cruze Eco I owned.

It was a little more basic, but at least it didn't malfunction!
So what is the ECO game on an 11 ECO 6MT? Mine just shows AVG. MPG & SPEED since last clearing & instantaneous MPG, Miles to Empty. Can I do more than that?
 
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