2007 Chevy Avalanche - Poor Gas Mileage

I’ve got a 2007 Avalnche with 5.3 V8 flexfuel, and 4.3 gears. I’ve heard of many people with this truck that get 20-22 MPG on the highway. The best I’ve ever been able to get is 17.5 MPG and as of late that has dropped to 16. I know that there are a lot of factors to think of here. So, here is some information:

Cruise: 75 MPH

Tires Stock: 42 PSI

Air Filter: K&N, Clean

Terrain: Flat

Oil: Mobil 1 5W-30, changed approx every 5K

Injector Cleaner: Run through about every 3K

Should I take it to the dealership to see if the computer can be re-programmed? Or is this just going to be my mileage?

I’d replace the K&N with a stock paper filter, clean the filter oil off the downstream components, and see if the mileage improves.

Fuel injector cleaner every 3K is a waste of money. Gasoline, ALL gasoline, has fuel system detergents in it by federal law. Additional cleaners should not be necessary.

At what speed do the people who get 20-22 mpg cruise?

I’m not sure at what speed many of them cruise at. However, I do know that 1 or 2 of them cruise between 70 and 75 as well.
When you say “downstream components” I’m thinking you mean MAF Sensor. However, what else is downstream that I can get to and clean easily?

Does this have Active Fuel Management? Does it stay in the V4 on the highway?

How much ethanol in your gas? Has your mileage dropped over the past 3 years?

If you slow down to 55-60 MPH, you’ll probably get 20 mpg. Otherwise, I’d bet this is just the way it’s going to be.

As long as you don’t over-oil the K&N, and let it dry 24 hours after oiling, keep the K&N.

Yes, it has AFM. It goes into V4, but doesn’t stay there for more than 10 or 15 seconds.

Not sure on the Ethonal. I just use regular gas. I’ve only had the truck for about 2 years, and yes, the mileage has gone down.

4.30 gears were not availible on the Avalanche are you sure you don’t mean 3.73 gears or 3.42 gears? If your Avalance is a 2WD model you should get about 15 MPG city and 20 highway. For a 4WD it’s 14/19. 17.5 MPG is right on the money for normal mixed driving. Your tires are likely grossly overinflated.

There’s likely nothing wrong with your truck. 16 MPG is perfectly acceptable mileage for this vehicle. It’s a full-sized V8 truck, what kind of mileage were you expecting to get?

17.5 mpg isn’t bad for this truck. If you run E85, that will drop your fuel economy. It will also increase wear on your secondary ignition components. Slowing down will help. Driving habits also make a difference, as do different drivers. My family and I took a trip last year, about 1000 miles one way, in a 2006 Grand Caravan. I could detect no difference between my driving and my sister’s driving, but I was getting 24-25 mpg and she was getting closer to 28 mpg. Same speed, same terrain, same driving habits, cruise on, a/c on the whole time for both of us. Sometimes changing the driver makes a difference.

Should this post have read “My truck gets better mileage than it should,do I demand the Dealer fix it”?

Everyone with a mileage issue should be aware that the EPA figures will be checked, you should also check, best before posting.

Exactly. It seems to be a reoccurring theme here. There seems be alot of people who have unrealistic expectations when it comes fuel economy. Questions like “My Malibu used to get 50 MPG now it’s only getting 25 MPG, what’s wrong with it?” are being asked with alarming frequency.

This has an EPA rating of 20 hwy, 15 city…and that was before the new testing protocols that more accurately reflect real world mileage. And with brand new stock tires. http://trucks.about.com/od/2007truckeparatings/a/avalanche.htm

If the truck has been checked out and is running properly, and considering that the testing protocols had to be changed because EPA estimates were often not being met in the real world, and cosidering that most areas use 10% ethanol mix now which lowers mileage, then I think your only choices are to accept this mileage or trade for something more fuel efficient.

You might be able to sqeak some more mileage out of it by getting some new and nonaggressive tires.