# Sudden loss in fuel mileage



## silvertank (May 26, 2015)

ive been having this random oil burning smell and the dealer cannot find a leak and now I've suddenly dropped fuel mileage from an average of 41 to 26 over the last 3 tanks. No power loss no lamps illuminated. Any ideas?


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## Merc6 (Jun 8, 2013)

How many miles do you have?


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## silvertank (May 26, 2015)

18k


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## diesel (Jun 8, 2013)

Winter fuel and colder temps will result in a 5-10% drop in fuel economy so that may account for part of it. The burning smell combined with a drop in fuel economy indicates a regen is in process. The thing is, there's no way a regen should last that long. Do your cooling fans come on after you shut the car off?

Thinking about this a little more, I am wondering if your car is somehow "stuck" in regen mode. I've never heard of that happening though. your dealership should be able to hook up the computer to the car to check the regen status, manifold absolute pressure, grams of soot etc and monitor what's going on.


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## obermd (Mar 3, 2012)

I'm thinking fuel leak from the high pressure fuel system.


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## silvertank (May 26, 2015)

It's going in Monday for a check so I'll keep y'all updated. No I've only had it regen with fans 2 times since I got it with 50 miles


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## diesel (Jun 8, 2013)

Yes, please keep us posted. This is a new one.


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## silvertank (May 26, 2015)

Dealer is still checking it but dpf and ash levels and regens are all spot on so they are not sure what's going on


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## Chevy Customer Care (Oct 29, 2011)

silvertank said:


> Dealer is still checking it but dpf and ash levels and regens are all spot on so they are not sure what's going on


Hey Silvertank, 

Let me know if you need an extra later of assistance. I apologize that you seem to be experiencing some concerns with your gas mileage. If you have questions or additional concerns, feel free to send me a private message. 

Patsy G
Chevrolet Customer Care


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## silvertank (May 26, 2015)

Hey Patsy it seems it was all taken care of thank you though. To everyone else dealer could not find anything out of spec and suspected it was either due to a relearn from being unhooked from the battery for a month or a bad tank of fuel. Just finish up a tank and averaged 38


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## diesel (Jun 8, 2013)

Oil burning smell must have been an interrupted regen. I have had some tanks of fuel differ from others in MPG. Also, keep in mind, these cars aren't the best for MPG in stop and go driving. In a week of winter stop and go driving, I have seen as low as 9.9 MPG for 25 miles.


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