[shook1]

I have a stock 2005 GMC Sierra HD crew cab that gets around 11 mpg with local driving. I was wondering if things like special air filters, spark plugs, synthetic oil and the like would actually improve gas mileage. I've seen T.V. advertisements, but I feel they may have been replacing worn plugs and dirty air filters with there new plugs and filters, which would have of course improved performance and mileage.

Has anyone seen actual improvement with such minor swaps?

[77 Canamman]

The issue with the 6.0 in the HD models is the pig rich fuel mapping from the factory. A tune will be your best bet to improve mileage and power in that application.

[hurryinhoosier62]

Originally Posted by 77 Canamman

The issue with the 6.0 in the HD models is the pig rich fuel mapping from the factory. A tune will be your best bet to improve mileage and power in that application.

Dittos. My BIL's got 10mpg AFTER he put a cold air kit, platinum plugs and synthetic oil in his 2500HD 4X4. His new Super Duty with the 6.2 gets 15mpg in stock form.

[PONTIAC-ONE]

Synthetic in the difs and transfer case ( I think the front dif already has synthetic?) and you can seek out tires that will maximize fuel mileage when you need new tires.
Big chunky tires & susp lifts are real bad for mileage.
The TUNE is something worth looking into, no experience here with that...yet.

[Old Goat 67]

Get a tune, 2005 Tahoe increased MPG by 3.5 @ gal. & 30 HP more. $120 I think.

Best money by far.

http://wait4meperformance.com/

[77 Canamman]

I prefer the Diablosport Intune, but some of the 6.0's in the HD's are not supported. The difference that it made to my 2013 Sierra 5.3 was amazing, with zero penality to the mileage. I dropped 7 tenths in the quarter mile, and disabled the Active Fuel Management. I have to use 91 octane fuel for best performance, but it is a small price to pay.

[geeteeohguy]

We have a stock 2006 Chevy 2500 at work, in mint condition, and it has been getting 8-13 mpg since new. It's a 6 liter, has good power, but is a big, tall (looks like a 4x4 but isn't) heavy truck. It sucks fuel like it was made in 1968. Comfortable, though!!

[shook1]

Originally Posted by 77 Canamman

The issue with the 6.0 in the HD models is the pig rich fuel mapping from the factory. A tune will be your best bet to improve mileage and power in that application.

Believe it or not, I'm unfamiliar with "tune". Obviously you're not referring to a "tune up". Please elaborate on a "tune". What is done, and how? Is it like what I see with those ricers and the laptops connected to them? Is it just a chip that plugs in somewhere? Lastly, is the cost worth the improvement?

Thanks, Luke

[Old Goat 67]

Luke,

"Tune" means that guy on the link I sent you will program another PCM unit for you with what you want in it, which you put in place of your original one. The original goes on the shelf or in your vehicle to put back in if you ever need too. He also gaurantees the tune for as long as you own the vehicle. Mine has been in my Tahoe since 2007 and it gave me 30 HP more (which you can feel) and jumped my mileage up from 19 mpg to 23 on the highway. Well worth the $120 I paid for it back then! Call the guy and talk to him.

Charles

[Ben M.]

Special air filters and spark plugs won't do a thing. My '95 F250 with a 460 gets 10-14MPG loaded or unloaded. The biggest difference? Ethanol free gas believe it or not is good for almost 3MPG.

[Formulabruce]

I own one and I "can" get 17 on a trip at 65 mph.
1, swap your 245 E rated tires for 165 E rated michelin "ROAD" tires, with groves
2, get a mileageXS super tuner, ( made by superchips) measure your tire, readjust your speedo, and set all your shift points to as low as possible
3, you should be ALL in and LOCKED up at 50 .
4. This is with a 4:10 gear on a gas 6.0. You can change your rear gear and front gears from a Duramax ( 3.73) as well, and there are plenty in junk yards.
Good luck!
http://www.servicemix.org/mileagexs.html