2008 GMC Yukon Denili

[91RS]

If you're getting 12-16 MPG then you're very unlikely to get better than that. You could change the gear ratio to a 3.23:1 maybe if you do a lot of highway driving but I doubt that would be worth the cost. The best thing you could do to increase fuel economy would be to learn to drive more efficiently. I can't really tell you exactly how to do that either because it changes depending on where you are (weather, terrain, etc.). You'll just have to try different things and see what works. I can say most people do not drive very efficiently, they drive so slow the engine is always accelerating or they WOT from every red light and race up to the traffic just to slam on the brakes. Smoothness is key.

 

[BG1988]

Unfortunately, 07-09 NNBS Tahoe's LS 2WD had the option of the 4.8/4L60.

the 4.8 was not too bad it got 20 on the highway(with my GMT800 silverado) honestly I'd swap out my Hybrid powertrain for one once this goes belly up.

with the extra low drag i could get probably get 18/24...


basically you only need the A/C condenser, engine ,transmission and drive shaft(from a 4.8L) battery positive cable as well as the ECM/BCM/TCM the rest is Plug and play(maybe VIN code and BCM programming?) to enable the back up sensor,and sun roof, mirror signals .. also hybrid debadging

 

[91RS]

The 4.8L is worthless unless you put a giant turbo on it. No power and the same fuel economy as the 5.3L. There’s a reason it was discontinued.

 

[avalonandl]

5600 lb SUV.....gas mileage....uhh no....

 

[swathdiver]

I have a 2008 GMC denili, is there any aftermarket parts to help improve my gas milage? And im sure i cant put in the cheap gas, but is it alright to use the mid grade gas? Any suggestions? Thanks

Keep it in top shape, replace all worn parts that can cause friction and slow it down, like dragging brakes. You can also change all the driveline fluids over to Amsoil or Redline, one guy with a pickup got 1 MPG improvement doing that just to his transmission. Run top tier, high octane fuel which will make more power and use less fuel. Run tires known for their efficiency and keep them aired up to improve MPGs.

 

[Doubeleive]

ya, sell it and go buy a 4 banger, even the new 2021 5.2 Tahoe with advanced cylinder deactivation is only rated for 18mpg

 

[Meccanoble]

The best thing we can do is get a truck that takes regular if you worried about gas mileage. My 5.3L gets 14.2 average gas mileage in the south with not much stop and go traffic. Thats not much better than your 6.2L. The pump is only place we can save. Once again, I feel bad for the 6.2 premium gas trucks but it cost to be the boss

 

[Joseph Garcia]

Welcome to the Forum from NH.

As folks have stated, the 6.2 was not built for great gas mileage. That being said, how you actually drive the truck will certainly have an impact on your gas mileage (I'm sure that I'm not telling you anything new).

Before adding mods to my truck, driving 'carefully and efficiently', I could get 12-13 mpg driving in the city, 15-17 on the highway, and 18-19 on the highway with my wife in the truck.

However, if you are like most folks with the 6.2, you are going to find it very difficult to drive the truck 'carefully and efficiently', as it is just too much fun not to.

 

[mikeyss]

I average 11 mpg with my 6.2 in town running E85. With red lights every 2 miles or less, I can't really get on it too much so that's why I feel l get 'decent' mileage. My 06 Sierra Denali with AWD gets 16 mpg in town, again I can't drive too aggressively because red lights are plentiful and closely bunched up

 

[BlackBearPerf]

Welcome to the forum. So many variables, fuel quality, octane, the foot on the pedal, driving conditions. Improving drivability, shifting and throttle response help wake the vehicle up. You can get some "smiles per gallon".