Hi I just bought a new 2010 chevy crew cab 2wd with the 5.3. Right now it says its getting 14mpg and I have been driving it very very carefully. It has the factory 20's on it and was wondering if a tune will help any on gas mileage and will I have to run 93 octane? I love the truck just thought it would do better than this. I had a 05 with the 5.3 and it got alot better than the 10 model.

 

it helped on mine started with 14.8 out the lot now im getting 16.0

 

are you running 93 octane? Man nice truck btw

 

Did the 05 have 20" wheels? They are one of the biggest killers of mileage.

 

You can have them tune for what type of fuel you wish to run. Yes, a tune can improve fuel mileage, just specify that when going over what you want out of a tune. How many miles do you have on it? A computer will take a bit of running before it "learns" the long term fuel trims.

 

no the 05 had 17 on it. Thats what I was thinking the 20's is killing gas mileage. Also it has around 600 miles on it right now.

 

It "should" get better as the mileage add up and it gets fully broken in.

That being said, I tuned mine specifically for 87 octane and it's a good bit more aggressive than stock, yet gets better mileage than a stocker. In other words, it runs a lot better than un-tuned, yet still gets better mileage. Win-Win situation.

I'd probably get some miles on it before condemning the poor mileage and/or any tuning.

FWIW, I lost an average (on my 4x4) of 1.5 MPG's when I swapped on 33's on wider 16.5" wheels, but comparable weight to 20's. I got it right back with stock size/height tires and wheels. I decided to ditch the big wheels and tires since they were purely cosmetic and worse in the snow than what I have now anyway. I know yours came stock with 20's, but just giving you my experience with heavy wheels and tires as it relates to gas mileage.

Nice looking truck by the way.