Bad Gas Mileage

[someguy]

Hello,

I have a 2009 Suzuki Swift+ Hatchback (aka 2009 Chevy Aveo). It has a 1.6l ecotech engine with 46,000 kms (28583 miles). I just bought this car a month ago and was expecting to get really good gas mileage. I do mostly highway driving and I can only average about 28mpg. Does that sound right? Seems like it should be much higher.

I brought the car to a garage and they tested all the sensors to make sure everything was all right. According to them everything was good and it didn't appear to be running rich.

Is this a common problem?

[Daox]

Bad highway mileage is usually due to a couple things:

1) high speed: The higher the speed, the lower the mileage. I am able to get 40 mpg in my 05 Aveo while driving the speed limit of ~55 mph.

2) brake use / tailgating: Brake use means bad mileage period no matter what speed. Tail gating means lots of brake use. Keep a nice cushion in front of you and you'll see better mileage.

[someguy]

I wish that was the cause; I drive like a grandpa. I don't normally go faster than 100km/h. Maybe I'll do a test and just do 90km/h. I can't see that getting me from 28 mpg to 40 though.

[Thymeclock]

I wish that was the cause; I drive like a grandpa. I don't normally go faster than 100km/h. Maybe I'll do a test and just do 90km/h. I can't see that getting me from 28 mpg to 40 though.

If what you say is true, it's not your driving style, it's the way the car is geared.

You should be getting 35+ MPG on the highway. At speeds of 65-70 MPH I consistently get 36-40 MPG with the A/C on. However, and this is important: once you leave the highway and are driving at speeds below 45 MPH you will be mixing it with "city" driving, which is 22-24 MPG at best, no matter what you do. That's due to no fault of your driving style - that's the way the car is geared, meaning it's the way the automatic transmission was programmed. Unfortunately there is nothing we can do about this.

These cars get wonderful highway MPG, but really disappointing city MPG: that's the 2009 Aveo experience. There are relatively few of these cars in my area, and now I know why: if you live in a rural state and do nearly all highway driving, you will love the MPG you get from an Aveo. Unfortunately I live in a city/surburban area and my "city" MPG (under 45 MPH) really sucks.

[someguy]

I wonder if this car is just a lemon? I do about 80% of my driving on the highway and that's when I see the gas gauge move the most. The tachometer is at the 2500 rpm mark when on the highway. That seems pretty normal to me.

[someguy]

Is that 35+ MPG(us) or 35+ MPG(imp)?

[2010AveoLT]

okay, when was the Last Service on it? usually Dirty Fluids and Filters, and Worn Spark Plugs are the first to make Mileage Suffer. next, look at your Tire Wear and Inflation Pressures; a Bad Alignment and Low Tires will cause undue stress on the Drivetrain, forcing the Engine to Work Harder to move the car, which in turn uses more fuel.

[someguy]

I'm not sure when it was last serviced. I bought it used about 4 weeks ago. The oil looked good. The plugs were good but had way too small of a gap. That was fixed. The tires are brand new but the alignment could be off. The place that did the tires did an alignment check and they said it was a little off but an alignment wasn't necessary. Also, the tires have the right amount of pressure.

I'm going to change the oil and put some synthetic in.

[someguy]

Are there any other idea's? Has anyone ever had this happen to their car then found a fix? Could it be a lazy o2 sensor? The mechanic said he tested it but maybe he didn't...

[someguy]

Could it have something to do with the discussion in this thread:

http://www.aveoforum.com/forum/f81/r...9-aveos-13419/