The best I got on a round trip to California with mine was 16.8. The truck had 1200 miles or so. Now I barely get 16-17. I stopped caring also cause I cant even touch 18-19mpg at 65 mph.......

 

one time, cruising 65 with a good 20mph tail wind, i got 17mpg for one tank one time only. but this was precam i think....

 

The best our 04 5.3 Yukon will get is 19mpg,if i am really careful.

 

These kinds of numbers I might be inclined to believe. 24.3 mpg from a 4x4 V8 SUV is unfathonable.....for me anyway.

 

last time i had a tail wind i only got 15

 

21 MPG (69 mi. trip - 14ST, 55HW)
- reg. cab
- 80 MPH
- 214 cam (untuned)
- 2800 stall (55mph lock up)
- 3.73 gear
- 28'' tire
- windows down, AC on (???? LOL)

Calculated today, using HP Tuners custom PID.... very freakin happy

 

I just came back from out of town.... my wifes cc used to give us 18-19mpg... I recently had a 87oct street tune done on it, and this past weekend it gave me consistant 20.5mpg driving at 70mph.... not bad at all, I wonder if it would get better with a 93oct tune/??

 

I just did the quick math on my mileage for the past two tanks and it came up to 19.25mpg overall. That's directly inline with where it's been for the past 2yrs, so I can't really complain. But it's a good thing this is a diesel, considering it's a 1 ton CC and I did have a trailer connected some of the time. This is also all speeds, not any set mph(didn't use cruise at all- because it's disconnected) and includes city and hwy combined.

It would be lower if I'd gone over 80mph for any length of time, but I rarely do that anymore. Am I getting old?