Fuel Mileage after mods

[Bvonscott]

So I have a 2016 GMC All Terrain 4X4 6.2, basically an exact replacement for the 14 I had. I don't really have any complaints about my truck. It's a pretty badass truck. Drives fast and is loud and mean. Nothing ever wrong with either my 14 or my new 16.

 

But after I swapped the AIRAID intake over and the electric cutout exhaust and put new off road wheels and tires I cannot get my average gas mileage to be above 10 mph. Now I do drive almost only city driving and I have for years, but it seems the new truck is getting worse than the last truck. Anyone else experience that and have a solution?

[cbrsilv15]

Did you disconnect your battery for 10 mins after installing the airaid? It fixed my problem.

[Rawyzf]

Might want to get a tune as well, I'm guessing you're running pretty rich if you're not tuned for the intake and exhaust dump.

[Silvern Sentry]

99% chance it is the tires, are the LT M/Ts? A/T would be much better for mileage if mostly city driving but too late on that I am guessing.

 

Also if you are getting your MPG from the dash and did not adjust your speedo then it is off if tires are larger. Need to hand calculate.

[TJay74]

I am going with tires as well, most people go with the narly looking off road mud tires. They are super heavy versus the stock tires. Then as said, if you changed the tire size and went with a larger tire than stock did you have the calibration adjusted for the new tire size?

[Bvonscott]

Thanks for the replies, no I did not have anything re calibrated. Do they even have tunes available for the 8 speeds yet? The tires are Toyo RT 18"

[TJay74]

Hypertech, HP Tuners and EFILive can all tune for tire size, but you take a warranty risk by using them as well. How much larger than stock did you go on the tire size?

[pcruis1]

I have Toyo RT, and I noticed a pretty decent drop in MPG after I put them on along with my lift. I had a tune done locally, and it helped quite a bit. Also, I noticed a little bit of a drop in my MPGs with the Airaid MIT under city driving conditions. Recalibrating your speedo (if you changed tire size) will help because the MPGs you're seeing on your dash are probably not accurate.

[Dnt]

Sling some mud in 2 whl drive just to make 100% sure that the trans is not stuck in 4whl drive. Post pics of the rooster tails.....VROOM

[Z45]

Put it back to stock!