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Discussion Starter · #1 ·
Wow.

I knew I was going through this tank faster than I thought I should. I tracked my mpg for the last three tanks...I'm currently averaging 24.8mpg. I drive 10 miles each way - all highway. I am between 60-65mph the whole way. I probably add another 10 or so miles at 40-45mph once a week.

Before the last few tanks, I was at around 30mpg. I'm not using the A/C anymore than I used to, I'm not idling the car. Nothing has changed in my driving habits. It got real hot for a few days but has stabilized.

I guess I'm just floored. I expected much better than this. Heck, with my old HHR I got 22mpg even with A/C on and city only driving.

My car is a 2013 Cruze LS. I use 87 octane - no ethanol.
 

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I'm assuming its a Automatic as well? I'd start, by trying some higher grade gas first. Maybe check your plugs, and see if they are gapped correctly..
Lots of us have noticed that using 87 causes studdering issues and some noted poor mpg.. Try 89 octane for 3 full tanks and see if that has taken care of your issue.

I'm running 93 octane for 3 tanks, then to 89 for 1, then back to 93.. I've seen my mpg increase by doing this. (most of my fills are between 5-8 gals of gas, and its almost every week day that its done).
I've not checked the gap on my plugs as of yet, but, when the weather gets better, I'll do that. Of course I'm running a 2012 Eco MT6
 

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Is your LS an automatic or manual? The automatic LS has abysmal MPG ratings, 22city/35hwy and 27combined. Even though your drive is what your calling all hwy, the distance driven 10miles means your engine/cat are not up to full operating temps. Short trips constantly would get a MPG number somewhere between your city & combined rating.

If your outside temps are above 80degrees try running some mid grade 89octane or even buy some gas with 10% ethanol(better engine knock prevention). Where did you find 87octane with no ethanol? Only stations that sell that here are not top tier.
 

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Discussion Starter · #4 ·
I would agree to change except that I've been running 87 for three months and this plummeted out of nowhere. THAT is my primary concern.
 

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I would agree to change except that I've been running 87 for three months and this plummeted out of nowhere. THAT is my primary concern.
What has your weather been doing? Is your car parked in the sun? If your weather is anything like the weather here the temps have been 80+ degrees daily and if parked in the sun the car is easily 120+ degrees.

There is also the chance you got some bad gas.
 

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Do you fill up at the same station all the time or hop around? I've gotten some tanks of bad gas before, and fuel economy did drop like a rock.
 

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Discussion Starter · #7 ·
What has your weather been doing? Is your car parked in the sun? If your weather is anything like the weather here the temps have been 80+ degrees daily and if parked in the sun the car is easily 120+ degrees.

There is also the chance you got some bad gas.
It has been in the mid/upper 80s but again...that isn't that different than what it was when I was getting better mpg. And no, I don't park in the sun - at work we have a garage and at home I have a cover.

Do you fill up at the same station all the time or hop around? I've gotten some tanks of bad gas before, and fuel economy did drop like a rock.
I always get gas at the same place. Three tanks in a row of bad gas seems really unlikely, doesn't it?

Could there be a mechanical issue causing this?
 

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Have you checked your tire pressures lately? Did you hit anything that might have thrown the alignment off? Are you carrying more cargo/passengers than you used to?

Another thing is that your E0 gas got diluted down to E10. That would cause a drop in fuel economy.
 

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Have you checked your tire pressures lately? Did you hit anything that might have thrown the alignment off? Are you carrying more cargo/passengers than you used to?

Another thing is that your E0 gas got diluted down to E10. That would cause a drop in fuel economy.
Definitely check your tire pressure. I have been running @ 32 PSI and I have barely topped 35 MPG with my Eco. The other day I checking my PSI after getting (so so MPG and increased to 40 PSI and put in a tank of 93 Octane BP and just returned with my MPG up @ 4 miles per gallon after driving from Cinti to Dayton and back and other misc driving.
 

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Discussion Starter · #10 ·
Have you checked your tire pressures lately? Did you hit anything that might have thrown the alignment off? Are you carrying more cargo/passengers than you used to?

Another thing is that your E0 gas got diluted down to E10. That would cause a drop in fuel economy.
I check my tire pressure regularly (I am compulsive ever since last summer when a tire blew out on the freeway! eek!) and they are consistently at 38. I haven't hit anything but I have noticed a slight drift to the right...

And my gas is E0 year round. Around these parts we have gas stations that are "100% gas" and never add ethanol.

And the only additional cargo is about 10lbs of books in the backseat. I would be sorely disappointed if that is what caused this..I mean...10 lbs! haha
 

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Get an alignment (slight drift to the right). Also, were you running the A/C before you noticed your MPG drop and are now running it?
 

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Discussion Starter · #12 ·
Get an alignment (slight drift to the right). Also, were you running the A/C before you noticed your MPG drop and are now running it?
Yep, A/C has been running the whole time. I'm a wuss when it comes to heat.

I just noticed the drift for the first time the other day...I thought maybe the road was angled (common around here) but on my drive to the store it did it again. I'm kind of ticked that the car needs an alignment at 3,300 miles. I haven't had a new car before...is that normal?
 

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Search for threads on spark plug gap and tire pressure. These simple changes will make a huge difference in fuel economy.
 

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Yep, A/C has been running the whole time. I'm a wuss when it comes to heat.

I just noticed the drift for the first time the other day...I thought maybe the road was angled (common around here) but on my drive to the store it did it again. I'm kind of ticked that the car needs an alignment at 3,300 miles. I haven't had a new car before...is that normal?
Normal, no; possible, yes. If you have really rough roads or hit a pot hole you could have thrown the alignment out. However, a slight pull shouldn't drop your fuel economy that much.
 

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I had a customer who was dealing with poor fuel economy, needed a locking gas cap. You could have the dealer check the fuel trims but really I agree the short trips are murder on MPG's, highway or not. Take it out on a long trip and see what she gets.
 

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Discussion Starter · #16 ·
Yea, the roads I drive on are all great, so that wouldn't explain it. Ugh.

And again, while I get that short trips lower mpg what concerns me is that this was the same way I was driving before, and my mpg suddenly dropped by around 5. That seems concerning.
 

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it could be some engine build up... These cars need to be driven... Find a good safe place, where you can do 70ish for 10-20 mins... with the better fuel, and you should see an improvement. I'll bet you've got fouled spark plugs due to the short trips..
 

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Discussion Starter · #18 ·
If that is really happening at 3,300 miles I am going to be ticked. 20 miles a day is not that unheard of. I have driven plenty of other cars just like this and NEVER had my mpg drop in this manner.

And, for what it is worth, I drove it 50 miles last night with an average speed of 68mph...I got 24.3mpg.
 

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Try a different gas station. If nothing else changed except maybe the fuel, change the fuel.

Also, dump a bottle of Gumout Regane or Chevron Techron Concentrate into the tank. It'll clean up any gunk that could possibly be in there.
 

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Discussion Starter · #20 ·
That was actually with a different gas station. I had to fill up before the trip.

I love this car, I do, but I am really irritated as to why the mpg dropped so far so quickly. Ugh.
 
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