# Fuel economy plunge



## Barry Allen (Apr 18, 2018)

So, just last week I filled up at a station that I hadn't visited in a long while (FS station in Central Illinois) because they were one of the lowest prices around and were conveniently along the way when I was almost empty.

Now I notice a HUGE drop in fuel economy. Like 20% or greater decrease. My highway fuel economy is struggling to achieve 43 mpg or higher when it previously was a steady 52 mpg or greater. Don't know about city other than half a tank is gone through the engine and it's shaping up to be one of the lowest tank averages for no reason I can find.

We should be coming out of winter so unless this station has a bunch of winter-blend diesel left over it should be getting back to summer fuel with a slightly higher BTU content. It's one of the pumps advertising 5-20% biodiesel, and with summer here (even though overnight low temps are in the 40s!) the biodiesel content should be back up to 20% or near it.

I'm just confused. This tank of fuel is going through the car quickly for no real reason.


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## JLL (Sep 12, 2017)

I wouldn't worry about it. After this tank, I would fill up at the station you normally use and see what happens. If it's still low then worry.


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## oregon_rider (Jul 21, 2017)

Barry Allen said:


> So, just last week I filled up at a station that I hadn't visited in a long while (FS station in Central Illinois) because they were one of the lowest prices around and were conveniently along the way when I was almost empty.
> 
> Now I notice a HUGE drop in fuel economy. Like 20% or greater decrease. My highway fuel economy is struggling to achieve 43 mpg or higher when it previously was a steady 52 mpg or greater. Don't know about city other than half a tank is gone through the engine and it's shaping up to be one of the lowest tank averages for no reason I can find.
> 
> ...


 Is this the same Cruze with the def/scr codes and CEL?

Jeff


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## oregon_rider (Jul 21, 2017)

oregon_rider said:


> Is this the same Cruze with the def/scr codes and CEL?
> 
> Jeff


 Looking at one of your codes....





__





P20EE: Code Meaning, Causes, Symptoms, & Tech Notes


The selective catalytic reduction system reduces oxides of nitrogen (NOx) emissions by injecting a metered amount of diesel exhaust fluid or reductant




www.engine-codes.com





jeff


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## Barry Allen (Apr 18, 2018)

oregon_rider said:


> Looking at one of your codes....
> 
> 
> 
> ...


Yes. The CEL was on with that code set before I refilled the DEF tank and before I filled up with a new tank of fuel from a station I hadn't visited in a long time.


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## rcruze (Mar 22, 2018)

What is your current mileage? I personally have seen the first third of my mileage have great mpg, the 2nd third it dropped, and now back to high mpg...


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## Barry Allen (Apr 18, 2018)

I'm just past 60,000 miles.


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