Chevrolet Malibu Forums banner
Status
Not open for further replies.

Bad Gas Mileage!!!

64K views 71 replies 26 participants last post by  BitingChaos 
#1 ·
It there anyone actually getting the rated gas milage. I have the 2012 LTZ with 4cly and 6 sp auto. No matter how I drive down the Interstate I can only reach 28mpg, and thats on a good day. With most of my driving being interstates and some around town my average through a tank is only 23mpg. I took it to the dealer to have it checked and they say nothing is wrong and blame it on the 18" wheels and my tire pressure being 2 lbs off.

When I took it to the dealer they gave me another Malibu with same engine/trans. I was able to get 32mpg on the 20 mile trip home. They had no explanation but to say my car in operating normally. There has to be something I can do. Any help would be great.
 
#2 ·
I have the V6 3.6. In daily driving I'm getting 18-20 and on the freeway I get anywhere from 23 to 29. One time I returned home (not in a hurry) 235 miles driving only 60 mph and got 36.4 mpg! Yes, that is calculated, not DIC.

Some of your mileage will be tire pressure if they're not up to 30 (or more like I usually keep mine). You can use the sticker on the door jamb and set them per GM, or experiment some but keeping them at or below the COLD max pressure (usually around 44 psi) to get better traction or mileage. Also, on a trip, if you're gonna carry additional load (people and/or luggage) you'll want to increase the psi accordingly.

The I4 usually gets great in-town mileage and even better freeway. Do you use cruise control? Do you fill up before a trip and then very shortly after? That is how to correctly measure your freeway mileage. Don't depend on the DIC to tell you. Some are pretty accurate and some are quite a ways off. My '09 V6 was almost dead on; my '11 V6 is always too high, sometimes several MPG.

Do you use the brakes while on the freeway? If so, you can instead tap off the CC (if used) or just let off the gas when you see traffic starting to cluster ahead. That way you're not converting kinetic energy (motion and speed) into thermal energy (heat from brake friction) and throwing it away.
 
#3 ·
It there anyone actually getting the rated gas milage.

When I took it to the dealer they gave me another Malibu with same engine/trans. I was able to get 32mpg on the 20 mile trip home.

Yes, I get pretty much what the sticker says.....both for highway and city.....
BUT only if I can do a flat interstate with no headwind and not over 65 MPH.
Any deviation from that, like a few town miles over a couple of days or keeping up with the traffic at 75 and it nose-dives toward the city figure.

By paying attention, I can eek out 32 on the highway and about 23-24 in town.

Are your figures based on the DIC display or on actual calculations over several tankfuls ? While most owners report that the DIC is pretty close, yours might be off a bit; tires might be a factor in that. If that is true, you might not be able to trust your odometer either. Long shot though.

What is your average speed on the Interstate ?
 
#4 ·
I just turned 3000 miles and have been using both the DIC and my calculations
.
The last trip I took I reset everything and did 70 in the interstate (5 below speed limit) and only got 28
.
Tires have nitrogen and are set at 32.

I have been running the 10% ethanol fuel cause its cheaper. Going to Texas next week and I'm going to try running only regular fuel...maybe thats the difference.
 
#5 ·
The last trip I took I reset everything and did 70 in the interstate (5 below speed limit) and only got 28

I'm going to try running only regular fuel...maybe thats the difference.
What kind of terrain? Flat or hilly ?

The fuel is not the ONLY difference.....as E10 is all I can get around here, and most places that I go.

Did the 18" wheels come stock with the car?
If so, the story from the "mechanics" at the dealership stinks.

There have been times when I couldn't get 30 at 70 but not many.

I think maybe you have something amiss.
I also think you will probably have a terrible time making anybody at GM admit that.

Your "test drive" in another car is probably the best evidence you have so far.
Maybe you should talk to the agency OWNER and offer to trade him.

Good luck; I think you will be needing some.
 
#6 · (Edited)
After 12K miles on a new engine, I recently took my 3.6 L 2008 LTZ back to the dealer for a check engine lite, crappy gas mileage and surging under moderate acceleration. Turns out that the CEL was caused by a "stressed" cable going to the purge valve. (Although the dealer wouldn't admit to it, was likely caused by the engine being pulled out twice - once to rebuild it due to high oil usage @ 47k miles - 2nd time to replace it with a new engine as the rebuild spun a rod bearing after 100 miles). They replaced the cable CEL turned off, but still crappy mileage. Over the course of a few thousand miles my mpg went from 24-25 mpg average mixed highway/city to 16-18. Dealer thought the poor mileage was due to the stressed cable and sent me on my way. Mileage was still bad. Not being a big fan of injector cleaning scams, Out of deparation, I reluctantly went to Autozone and bought a bottle of Lucas injector cleaner. I've had good experierence with other Lucas products, so thought I'd give it a try. Added it to a full tank. The surging improved almost immediately and after about half the tank, my gas mileage came back to 25-26 range (30-32 @ 70 MPH highway).
 
#7 ·
I've had good experierence with other Lucas products, so thought I'd give it a try. Added it to a full tank. The surging improved almost immediately and after about half the tank, my gas mileage came back to 25-26 range (30-32 @ 70 MPH highway).
Others may find your experience useful.

I like Techron for routine use and Berrymans B12 Chemtool when there is an apparent problem but will give Lucas a look next time.
What was the exact product that you used ? (assuming that there might be more than one that claims to clean injectors).

I don't think it applies to HIS situation however, since he has no other symptoms (that he has mentioned anyway) and the engine is practically new.

No auto maker guarantees any particular gas mileage and it can vary from one to another just because of manufacturing tollerances. Getting poor mileage "fixed" when no other symptoms are present will be almost impossible, I think.

His dealer should at least hook up a scan tool and check all the parameters that they can.......while the car is going down the road too......and look for other obvious things, like dragging brakes or a slipping transmission due to low fluid. Just writing the complaint off with "we don't guarantee mileage" would not be an acceptable answer for me. If they really can't find anything, that might be different.
 
#8 ·
I agree that there are other products on the market but this one worked for me (so far).

Lucas Oil/5.25 oz. fuel injector cleaner
Autozone Part Number: 10020

I haven't been a big "believer" in injector cleaner since I suspect that caused the fuel pressure regulator on my 93 S10 Blazer (4.3 Vortec) to fail twice. Haven't used it since in the Blazer 140K miles later (230K total).

One of the things I liked about the Lucas injector cleaner is that it claims to not use any solvents.
 
#10 ·
Seafoam is excellent too. I never believed the hype nor really put much faith in any cleaner like that.
Now I admit I don't take care of the lawn mower at all. It is used to cut grass so why baby it? Anyways I always leave the gas in it year round, rarely clean the air filter, unless it won't even run and same with spark plugs.
Last summer the thing was running really crappy so I tried cleaning the air filter and putting in new plugs but it still ran crappy. I decided I'd give that Seafoam stuff I heard about a try since it was on sale at Autozone. I poured some in the gas tank and directly into the carb. It smoked a little then it started running great. I was really impressed.

Does anyone else use Seafoam?
 
#13 ·
No question that it does good at some things, under some circumstances.

Probably a dozen or more other products would have too.
And most of them would have been cheaper.
And most of them wouldn't claim to be able to cure a myrid of other engine ailments, some real and some imaginary.

Seafoam was originally formulated to be a fuel stabilizer for marine engines.
It's use for other things is largely due to hyped marketing claims.
AND lastly, while their sales are going UP, the price is going UP too.
I'm not saying that their product is useless; I just don't like the way they do business.

I prefer to use stabilizer for stabilizer and cleaner for cleaner.
I guess I'm funny that way. ;)
 
#15 ·
OP check your spark plug gaps to the recommended gap from GM. On the sonic forums and some others, the mfg of the plug is shipping them with smaller gaps than what GM suggest. Some sonics are showing .019-.028 and that's just between the 4 plugs that are installed. GM calls for mid 30's on that car. NGK is the MFG for the sonics plugs and they say .027 for the plug that comes with the car. Might be nothing, but it's worth checking
 
#17 · (Edited by Moderator)
I have the same problem. 2012 Malibu 4cylinder. It is supposed to get 23 city 33 hwy. I get 20 if I am lucky COMBINED! Brought it back many times. Dealer says yes mileage is low but everything checks out fine. The guy in parts has the same car and gets 26 combined! Told me to use Techron in fuel. Did that now mileage is worse!! It makes a horrible noise on start up like something is grinding. I'm going to record the sound on my phone to bring it into the dealership. I have someone from Chevy call me but they just help resolve my problem with dealer. Dealer says they are following chevy specs looked up bulletins etc.. Can't find a problem. I had an old 2002 Hyundai Sonata 6 cylinder that got 24 mpg combined. I got this thinking I was getting better gas mileage and wanted to buy American. I should have bought another Hyundai. My husbands 2007 Sonata with 6cyl gets 23 combined. No resolution thinking of going to small claims court like the lady with the Honda.

Any suggestions?

Yes, I appreciate it since I have the same issues (see Poconomom) with NO RESOLUTION! I'm tired of going back and forth to the dealer. Looking into lemon laws and civil suit. There is an obvious problem but no one adimits to it.
 
#18 ·
Are you using Top Tier gasolines or Mom-n-Pop varieties? If you research Top Tier fuels you may gain some insight on how the fuel can affect your mileage.

But what you haven't told us, and what is extremely important to a discussion on poor mileage, is how you're driving. Are you in a lot of city traffic? Do you idle a lot, like in drive-thrus, at school waiting for the kids, or at traffic lights? Do you use the remote start feature extensively? Do you use cruise control on the freeway, or do you tend to follow other drivers and then when they change lanes do you drive up to the bumper of the next one ahead of you and then use the brakes?

A lot of folks that I see on the roads use extremely poor driving habits and wonder why their mileage is so dismal. I'm not saying your habits are bad, just relating that it's an area you need to examine before bashing the car.

I have a V6 and get over 19 mpg average in its life of over 29,000 miles. On the freeway I get 27-30 mpg, and in the city (depending on season) I get 18-20 mpg. I'm not afraid to use the skinny pedal, either, but when I'm on the freeway I drive to get mileage. In city traffic I use roads with less traffic on them to keep from watching my gas disappear, and the spin-off benefit is I'm not polluting as much.
 
#19 ·
I haven't been able to average more than 19 to 29 MPG no matter how I drive that car. The tire pressure is fine. I emptied the trunk. I can't get any better gas mileage. I have a 2011 Malibu 4 cylinder. I get better gas mileage from my 2003 6 cylinder. The dealer says there is nothing they can do. As soon as I pay this car off I'm getting rid of it and NEVER buy another Chevy. And I was a Chevy girl. I will not recommend Chevy to anyone anymore. If they can't stand behind their product then I'll go to a brand that does.
 
#21 ·
This is why I never buy bargain gas, and why I insist my girlfriend does the same. Always buy from good brand names like Shell, BP, or Exxon. I also change my oil within 5000 mile intervals and use fully synthetic oil.

I haven't been driving forever, but I drove an 89 Camry from 50k to 120k miles without ANY loss in fuel economy or need for injector cleaner, and 45k flawless miles in my Malibu V6 achieving 18/28 mpg.
 
#22 ·
Seems like the same story all around. When I started this thread My 2012 had 4000 miles and now I have almost 11000 miles and nothings changed. city driving gets me 20mpg and the best HWY driving has ever gotten was 29mpg. AND YES this is using the best fuels and trying to drive as efficiently as possible. I still like the malibu I just wish I would have gotten the V6 so at leat with the bad gas milage I would get a little pep. thx for all the posts...
 
#23 ·
At 29 mpg, have you lifted the hood to make sure it's a 4 and not a 6? Just seems odd that you can't get mid-30's like so many others.

Heck, I even got 36.4 one time and one time only (so far) while driving 60 mph from Knoxville, TN, to Louisville, KY. It was October 2011, and it was 234.8 miles using just 6.453 gallons. Funny thing is my trip meter said 234.8 and my odometer difference from the previous fill-up was 264 miles. I must have written down one or the other incorrectly, and I think it was the previous odo. The DIC indicated 36.5 when I filled, so when it calculated out to 36.386 mpg I was elated! And it only took setting the cruise on 60 and then just steering it. I only had to get up to 65-70 a time or two to wiggle out of heavy traffic, but then I took my foot off the gas and settled back into 60. I'm gonna try it again someday, not sure when, and see if I can get it again. I don't consider it an anomaly, but instead it's a rare event that I drive less than the posted speed limit.

If I calculate driving only 234.8 miles on 6.453 gallons I get my posted 36.386 mpg. However, if I use the odo difference (rounded to nearest mile) of 264 on the same fuel, it calculates out to 40.911 mpg. I highly doubt I did that good on a V6, but if I could do it again I'd reconsider that statement!
 
#24 ·
Just bought an 08 Malibu V6, 50k mi.
Full tank last night, drove to work and back (60miles), gym and back (maybe 10miles) and now down to almost a half tank...WTF! This doesn't seem anywhere close to what it's suppose to be doing. I had an 02 Impala b4 this with the 3.4 and got close to 28-29 highway with 160k miles on it...
Should I be looking into returning this car??? :(
 
#25 ·
Does the fuel economy readout also say you're getting terrible fuel economy? Use midgrade or better gas, maybe get some injector cleaner, make sure the oil is changed and using fully synthetic oil as recommended by the manual (Dexos 1 certified). It may have been abused during its ownership.
 
#27 ·
Oh I filled it myself Sunday night expecting to only need that gas for the week, like I normally did with the impala. It was reading 20-21 average mpg...it's 99% highway driving for me to work and back. I don't like this at all! lol Could have got a truck with better mpg than that.
 
#31 ·
Yep.
New front O2 sensors in my Yukon got me back 1.5 mpg that I slowly lost over the years/miles. Sensors get "lazy" as the miles rack up.
Sensors were at the edge of "acceptable" in the system, no codes or SES light.
 
#30 ·
Sounds like it was premature complaining! No offense, haha.

Get to know the car and go through a few tanks and report back to us. Also, you should still follow the tips we laid out for achieving good FE.
 
#32 ·
We bought my wife's 2008 malibu (4 cyl) brand new with 4 miles on it. Now it has 52K and the mpg is around 15 in town and 26 on the highway. I have changed the air filter. I change the oil every 3K. I don't have any problems lit up on the dash board. I have used fuel injector cleaning fluid. I really don't know what else to try. My old 02 Trailblazer gets 16 mpg. Any suggestions?
 
#34 ·
I'm averaging 21-23 MPG combined at an average speed of 75mph HW, 45mp City (Tampa). I was getting 25 combined before I started going to the dealer for oil changes and I didn't even think of that until I read this post. I thought it was the 20" wheels but my millage went down right before I put them on. Crazy I went to Walmart before and chose my oil then Chevy and they recommended my oil. 32-33 PSI serves me well good traction soft rid even with the large wheels no increased road noise or stiff feeling. Don't let them blame the wheel size because I have heavy 20" wheels on mine.
 
#35 · (Edited)
Sorry, big wheels do indeed kill your mileage. That's a fact. 4-cylinder malibus are engineered for 215 R17 inch wheels, with the exception of the relatively light 10 spoke LTZ wheels that are 225 R18s. Not only weight brings mileage down but the larger contact patch (I'm assuming your 20s are 235s or wider) and additional leverage needed to torque the larger diameter wheel around.

Adding big wheels is a pretty thankless modification. 21-23 mpg sounds about right.

If you want to maximize your FE, go out and buy Mobil 1 fully synthetic 5W-30 and use that for your next oil change. Dealer will put in the oil if you buy it and tell them to use it. Whatever you get during those miles is the best you'll get with 20s on the car.
 
Status
Not open for further replies.
You have insufficient privileges to reply here.
Top