Mazda3 Forums banner

Poor Gas Mileage on 2007 Mazda 3

29K views 16 replies 14 participants last post by  Vetrayed 
#1 ·
In the past year or so, I've noticed my gas mileage start to decline. Here's my car info:

2007 Mazda 3 i Touring 2.0
60,000 miles
--------------------------------------
I consistently get 23-25 mpg. Over the course of a week, I drive about 80% highway, 20% highway. I recently drove from Boston to DC (100% highway) and my gas mileage was about 26.

Here are some things I tried to improve the GM:
changed the air filter
made sure tires are all the same pressure
flushed tranny fluid
changed oil
drove less aggressively

Does anyone have some suggestions as to why my GM is low? Is 25 MPG normal?
 
#4 ·
I have a 30-40 minute ride to work every day. It is all highway. My speed average 70-85 mph and I average about 25-26mpg. I have an 05' 2.0 ATX. On longer trips I get better around 30ish. Ive noticed its not necessarily the speed, but the consistency of speed. I use my cruise as much as possible and it seems to help.
 
#9 ·
[quote author=P8N49025 link=topic=187562.msg3968927#msg3968927 date=1300687224]
Lucas Oil Fuel Injector Cleaner is the best.
[/quote]

No it is not. Not by a longshot.

You need a Fuel System Cleaner that contains PEA (which Lucas does not). That leaves a very short list:

Redline SI-1 (as mentioned above)

Gumout Regane (in the clear bottle)

Chevron Techron (fuel SYSTEM cleaner......not the fuel injector cleaner)
 
#11 ·
[quote author=g3ck0 link=topic=187562.msg3997544#msg3997544 date=1303172093]
Wow, I gotta try this stuff out. I'm happy to get 21mpg on my car!
[/quote]

Something has got to be off. I have a 2007 i 2.0L . I've consistently gotten 36-38 MPG since I bought the car.
 
#12 ·
[quote author=Greggy_D link=topic=187562.msg3997577#msg3997577 date=1303176215]
[quote author=g3ck0 link=topic=187562.msg3997544#msg3997544 date=1303172093]
Wow, I gotta try this stuff out. I'm happy to get 21mpg on my car!
[/quote]

Something has got to be off. I have a 2007 i 2.0L . I've consistently gotten 36-38 MPG since I bought the car.
[/quote]

2.3 L doesn't give the best mpg. I'm getting around 23-25 mpg 80% city 20% highway. Best mpg I've gotten was 29-30 mpg 100% highway.
 
#14 ·
Mileage of the 2.3, in particular, is quite sensitive to driving style. If I short shift and avoid heavy throttle, I can get 28 mpg in town and 34 on the highway. But mileage really suffers above 70 mph--at 80 mph, it's back around 30. If I drive my 3 like I do my Miata, the mileage falls off a cliff.

BTW, the trip computer's mileage display is inconsistent, and usually about 2 mpg lower than reality. You have to calculate from miles and gallons when you fill up.
 
#15 ·
Tip 1: Let your car warm up to running temp before driving, when the entire engine is warmed up the car will be more efficient as a whole. And the engine will last a lot longer this way.

Tip 2: Greggy is correct about the injector cleaner. Gumout Regane with every oil change (still put it in the fuel tank!) will make a huge difference in mpg.

Tip 3: Spend the extra few cents on good gas. I switched specifically to Shell gas, after using whatever was close and got about 30 more miles to the tank on average.

Tip 4: Clean/Replace your Air Filter every 10,000 miles, your plugs every 30,000, your PCV valve with every (or every other) oil change, and change your oil at least every 3000-5000 miles, no matter what miracle oil you use.

Tip 5: It may sound stupid, but make sure you use 5w20 (Maybe 5w30 in some cases) oil, either synthetic, or synthetic blend. Preferably a european certified oil. It is lighter oil, and holds up better than the American standards. Lighter oil lets everything move easier, which gives you better gas mileage.

General rule of thumb with these engines are 5w20 for mpg, 5w30 to protect seals, and help prevent dry starts. Mazdas shouldn't need anything higher than that unless they are EXTREMELY built.
 
#16 ·
[quote author=g3ck0 link=topic=187562.msg3997544#msg3997544 date=1303172093]
Wow, I gotta try this stuff out. I'm happy to get 21mpg on my car!
[/quote]

I just wanted to throw my two-cents in on this topic. Last week I bought some Regane Gumout, at the suggestion of the posts in this topic. I put it in my empty gas tank and filled up. Right now my gas light is on and i'm at about 350 miles driven. So that equates to about 30-31 mpg.

Maybe its the placebo effect, but I'm pretty happy with this. I do mostly city driving, a few on the highway here and there. I thought my gas mileage was dwindling before this, so I hope I got some gains from the Gumout!
 
#17 ·
I would still check everything else, and make sure your spark plugs are good, using injector cleaner gets you better gas mileage, but does make your plugs work harder, and they can get a yellow ceramic-like coating on them if you use too much gumout (or too high of an octane), to help prevent this when you change your plugs get one step colder. In NGK plugs it's just one number up, for example if your car calls for a TR6IX, you would want a TR7IX. (Someone correct me if I'm wrong about the numbering for NGK)

But yes, gumout regen = better mpg.
Shell gas = better mpg

Gumout is made by a company branched off shell.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top