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Discussion Starter · #1 ·
Hi Everyone,

Couple of months ago I bought a used 2012 cruse 2lt with 36000 miles on it. No matter how I drive I have never got more than 34 to 35 MPG. I drive 80/20 highway/city. I have driven it on cruise control at 55 MPH, 60 MPH and 65 MPH to try and see at what MPH would the Cruze give maximum mileage, but apparently the maximum mileage I could get was 35 MPG. I drive to get the maximum mileage so I never floor it nor do i drive fast. I usually drive it at 60MPH on cruise control. I can't figure out why am I not able to squeeze more mileage out of it.

I also read on this forum that mileage is different for ECO, LT and LS models. Does the 2lt only give 35MPG??

would changing spark plugs make a difference?


Thank You in advance.
 

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I would suggest a few things to achieve higher ratings. First is regap your spark plugs to 0.035". Second thing is inflate your tires to 40psi.(I know the ride might be a little out of your comfort zone on the road, but it helps a lot). I would run either a 91 octane fuel in your cruze or 87. 91 has shown to be the best solution. And lastly on my mind for now, is make sure your not getting brake lag. (Meaning your pads aren't sticking creating friction to the rotor causing them to try and slow down the car while your moving when you don't want it to stop yet). I had a LT before my eco and I could only achieve 38 or 39 mpg. And I did all these things I told you. Im sure what I told you will help. =]
 
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Discussion Starter · #3 ·
Thank you for your quick response. I would start with regaping my spark plugs to 0.35.
Talking about gas, yes i always fill up 91 octane and my car seems to love it :)
About tires, I used to run 40 psi but as you mentioned the ride was rough so I deflated it back to 32 psi and the ride is much better now.
 

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Honestly...I haven't ran 91 octane in my eco yet...and im getting great numbers with 89 octane. Is yours a manual or automatic?
 

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okay. This is good news still. Idk if your aware of this or not, but in the autos, there is an option for you to shift it like a manual. They call it driver shift control. All you do is move the gearshift over to the M on the shifter, and push or pull the shifter up or down. The Plus is up to go up a gear, and the minus is below to go down a gear. I would shift gears at around 3k rpm so you don't over rev it..but you can shift it whenever really. Im here to help you on anything you need help with. There are a lot of others on here that are more than happy to help as well.
 

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Your welcome =]. Using this feature does help some...as long as your shifting is timed right. Just like a manual, if you shift when your suppose to, it helps mileage. But unfortunately the autos don't have a shift light in the DIC. The best source for knowing when to shift at the right time in DSC to achieve better mpg is to contact Chevrolet to see what they recommend. Ive always done the first three gears at 2500 rpm and the last three at 3000 rpm and I got good numbers with mpg. Also I would recommend putting dialectric grease on the plugs and a little on the inside of the boots. This will help with any rough idles and running in the future as long as you keep up with it as well. My dads 2011 Malibu is/was doing that and I put new plugs in and applied dialectric grease in. And whala it is gone with the rough idles and running.
 

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What is your weather like? my 2012 1LT auto I usually only average 32mpg with 60% city when cold out. The 2012 automatic sweet spot on the highway for mpg is 45-70mph, ramp to ramp highway at 65-70mph I can meet the window sticker 38mpg highway even in the winter. 75mph I only get 31-33mpg.

The 2012 1lt, 2lt and LTZ automatic are all rated at 26 city 38 highway 30 combined. Most drivers will average close to the combined number so anything higher than that your probably doing pretty good.
 

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For an 80/20 highway/city driving split, you're actually doing pretty well for fuel economy in an auto Cruze. The speed will make a big difference. Don't go above 65mph and you'll be able to do far better. CC2012 brought up the good points that you need to look at. Gapping the spark plugs is a big one. Raising tire pressure will make a slight difference. If 40PSI is too much, go somewhere in between. Even if you go to 35PSI, it will still help.

The highway rating of 38mpg is for 100% city driving. That 20% will ruin it for you. What's your average speed?

Also, what state do you live in?
 

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Vehemently disagree with increased spark plug gap, I dumped those NGK's that cam with it, they have ceramic problems, had so for years. Replaced with Autolite double platinums and gaped at 26 mils. Stupid springs inside of those rubber boots were to short, so I did stretch those out.

Besides using only Mobil one dexos, that is all I have done to my 2012 2LT. I hate ethanol with a passion, only use top tier 91 gas, ethanol free.

If I can hold my speed to 65 mph on the interstate, average 44 mpg on long trips. But this is with summer gas, 35 mpg is more typical with winter gas. Only thing I can do with winter gas is to cuss at it. Idiots, just for an extra minute or two warm up time that is costing me a small fortune in winter time. Never learned how to deal with idiots, but unfortunately for the rest of us, they are in charge.

Switching on the AC in above 32*F weather with the defrosters on is equally stupid, with that cold oil tears apart the seal in the AC compressor. Get around that by opening a window. Also using the AC around town overloads the cooling system so don't use that either.

Figure if I can do a 25 forced march in the military in 100*F weather with a 65 pound back pack on with full clothing didn't kill me. Driving around town even in 95*F weather would also not kill me just sitting there, and no back pack on wearing a tee shirt. So far, it hasn't.

Been using anti-seize on the spark plug threads for years, if you don't with an aluminum heads, the treads inside of the head will come out with the plug. Did one of those recently with plugs that were in for 70K, took me an hour per plug to very carefully work them out with plenty of PB Blaster. When the wrench became difficult, screwed that back in. Not going to repeat my language here while doing this.

Same with using dielectric grease on the boots, Even made my own tool for this, with a U at the end of hardened steel bent at a ninety degree angle to pull up from under the boot. But this will not work on the Cruze, no way to get under there.

If they wanted to use aluminum heads, could have put steel sleeves in there, but as usual, the stockholders come first.
 

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Discussion Starter · #12 ·
yup true. I am planning on gapping the spark plugs as well. BTW I do have noisy and rough idles. And today on my way back home from work I will try and shift manually. I used to drive a manual car for 6 years so it shouldnt be an issue at all :)
 

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Discussion Starter · #13 ·
Hi spacedout,
I used to live in florida and these mpg numbers are from when I used to live in florida. I recently moved to north chicago and I don't even bother to check my mpg anymore cause I am pretty sure it would be in low 30's because of the cold weather and moreover I start the car and let it heat up fo 10 minutes everyday before I start driving(so fuel is wasted when the car is idling for atleast 10 minutes everyday).
 

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Discussion Starter · #14 ·
HI xtremerevolution,

Yes you are right. Even I think the 20% city driving is ruining it for me because when I am cruising on highway the "instantanious fuel economy" shows 44 to 45 mpg and I know that the DIC is a little too optimistic when it calculates MPG but I am sure I might be avergaing atleast 39 to 40 MPG on the highway.

ya 40PSI is too much I think because the roads here in north chicago are bad and i felt things would start rattling if I don't deflate my tires.
 

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Hi spacedout,
I used to live in florida and these mpg numbers are from when I used to live in florida. I recently moved to north chicago and I don't even bother to check my mpg anymore cause I am pretty sure it would be in low 30's because of the cold weather and moreover I start the car and let it heat up fo 10 minutes everyday before I start driving(so fuel is wasted when the car is idling for atleast 10 minutes everyday).
Well don't worry about warming the car up it will only reach a certain spot then won't heat anymore too small of a displacement motor to accumulate heat while not in motion.
And you will get better fuel milage since your out of Florida the don't know how to drive no offense Danny.


Sent From My Galaxy Note 3.
Which is bigger than my hand.
 

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One more thing I have done, is drill out my air box. If i recall the base of the air box is like a grid. I drilled a bunch of large holes to improve the breathing, and performance. So far, I'm using a convetional air filter, you can always change to a K&N or similar performance air filter.
If I didn't have a heavy foot, my milage would increase...but I'm one of those...gotta be in front of you, I will not settle for second place...haha. As well, I have noticed a boost in performance with this mod.
 

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HI xtremerevolution,

Yes you are right. Even I think the 20% city driving is ruining it for me because when I am cruising on highway the "instantanious fuel economy" shows 44 to 45 mpg and I know that the DIC is a little too optimistic when it calculates MPG but I am sure I might be avergaing atleast 39 to 40 MPG on the highway.

ya 40PSI is too much I think because the roads here in north chicago are bad and i felt things would start rattling if I don't deflate my tires.
I live in New Lenox, and commute to Downers Grove. Not quite Chicago so the roads are decent, but I run 51PSI year round on my all-seasons and 40-42PSI on my snow tires. 34k miles and no rattles to speak of. The fit and finish on these cars is superb. That said, you will feel the change in ride quality.
 

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Mom moved to North Chicago when I was in the military, is it still there? 1415 Commonwealth Ave. as I recall, loved that North Shore line, they should have never removed it, could have switch to diesel. I moved her to the north shores of Waukegan when I got out. Poor mom didn't last very long, died a year later. Sorry for posting my memories.

35 psi for tire pressure seems to be my best compromise. Stepdaughter move to N Lake Shore Dr. In Milwaukee, just moved her out to Brookfield a couple of weeks ago. Thought my Cruze was going to fall apart, but carried a bushel basket to pick them up.
 

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I have a 2013LT and i'm getting around your numbers as well driving a bit more highway. In one tank I drive 500 miles highway, and about 20-30 miles city, getting between 36-39 mpg, depending on how i'm feeling.

You said you rocked 32 psi because you didn't like the ride at 40, but knocking that up to 35-36 like Xtreme said will still give a noticable bump to mpg, and shouldn't be anywhere near as bad as 40, 32 just seems too low to me.

Let us know how it goes after the gapping and anything else you do. Good luck!
 
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