I was just wondering what everyone here is getting for mileage on these things. My old 6.2 Blazer was bone stock except for the exhaust and oversize tires, and it got nearly 24 MPG on the HWY, and better than 20 city. When I sold it and bought the 6.5 Turbo one I have now, I expected to see better performance and mileage, I mean c'mon, this truck is computerized, more aerodynamic and turbocharged right? I was lucky if I got 18/19 on the highway when I first got it, and up until about a month ago it seemed to be getting progressively worse, and so did the power. My wife drives it now as much as I do but it was so bad we were only getting about 400 miles on a 30 gallon fill-up! I'm hoping the recent modifications I've done and the exhaust I'm planning to do will help, but I just wanted to see what everyone else is averaging, and what seems to help them the most. ThanksEdited by: Texas Diesel Guy

I get about 20 to 21 on the highway with my K3500 4x4 Crewcab Dually. The nice thing is it stays about that with my 5th wheel on as well.

12-13 towing 12K load


15-18 depending how heavy a foot I have in it, did record 22 once probably a calc fluke but I was also running 55mph following my Dad across Va. I don't see much 55mph myself usually it's 75+ for me


16-17 avg for 70-75 mph with 3:73 & 285-16s

I guess you traded economy for a little horsepower.
I get 15.5 avg. all driving. It doesn't drop much towing.

the best i have ever gotten was 18. mine is usually between 15 and 17. cant complain i guess. lot better than my old truck which got 10.

I've never towed anything with mine, and I would also like to note the poor mileage I posted earlier was months ago. Since then I have done some front end work, new tires, obviously some pump mods and cleaned the K&N. All have contributed to a very noticeable gain in power/mileage, though I have yet to calculate because I'm still trying to burn off the last tank I bought, and hope to see even further gains with the new exhaust I'm getting this week.

On the highway best I get is about 23 mpg, cruisin at 65 mph. In the city its more like 15 mpg. pretty variable though depending on driving style. My truck is Naturally aspirated though if that makes a diff.

Seems like best mileage with these engines is in the 1800-1900 rpm range, so if your not geared for this your mileage will suffer (this is the main reason why the dualies get worse mileage), my truck has a 3:42 ratio with overdrive so my highway cruisin is pretty much in the zone. Also a lock up torque converter makes a big difference.

hard to beat the ol 6.2s with a TH700R4 and 10 bolt rears for mileage, the only thing that killed them was hills, you might not even know you were going up one but the truck sure does.