Yukon MPG

[Bevl Hvn]

2003 4x4 Yukon, 20s, stock - 14.2 every tank - I commute 25 mins each way to work + errands etc. Went to 16 when I drove 11 hrs, 1 way empty trailer, back with 2 bikes in the trailer and a wad of parts in the back. On cruize control set to 60 both ways milage was the same. I run regular unleaded.

[goinbig]

'00 Yukon Denali
Vortec 5.7L; 4wd; tow package; 3.73 gears; stock wheels/tire size.

I get around 12mpg in the city and between 14 and 15 on the highway if I keep it around 70-75mph...any faster and the milage drops FAST

[rgloston]

tonytone... My Yukon came stock with 3.73s. One can learn a lot with VINs. The only time I ran on a straight hwy trip, and ran it til the idiot light came on was when I ran a long haul from Jackson, MS to Atlanta, GA (Northside). Even then, I was running at 80mph the entire way, stopped a few miles past the GA state line to gas up again. Trip only showed 365 miles driven. I remember this because cuz my friend ragged me for buying a huge vehicle that got less than rated mileage for a single guy with no kids. Only put 24 gallons in tank when I filled up. Surprised that the idiot light came on.

At least I know how much fuel is left when the light comes on. My Yukon was completely stock from intake to exhaust back then. I later purchased a HPPIII, and saw no difference in mileage, but performance increase was barely present. I returned everything back to stock, and sold the PPIII. Building up a 5.3L to put in my '86 C10. That's my toy from this day forth. Going with a dyno tune, headers (no brand decision yet), Flowmasters (50s, 80s, or HP2s), cam & springs, and a 4L60E w/ high stall (probably a 3K).

[tonytone]

rgloston--FWIW I ran the tripmeter after filling up for a relatively short <100 mile return trip from the SF Bay Area back home to the Sacramento area this past Saturday. DIC showed me averaging 16.9 mpg on the trip, w/ an average speed of 60 mph--even given that the majority of the return trip was done between 70-75 mph since it was mostly freeway (maybe around 10 miles of surface streets). 16.9 may not be much for a 5.3L but for 6-liter it is fairly impressive indeed, IMHO.

[rgloston]

Yes, it is indeed. I can believe 16.9 MPG for a 5.3 and a 6.0. What I find hard to believe is claims of 20+ MPG on either of those engines (no matter what speed is driven). Though the 2003 & up 5.3s/6.0s (even soon to come 6.2s) have been EPA rated for 18 hwy, anything over 20 is questionable. I would have to see that in person to believe it. I would openly admit to being corrected, IF I see with my own eyes.

[tonytone]

I think 20+ mpg out of a 5.3L is not entirely impossible, given some tuning mods to the PCM and ideal driving conditions (e.g., no cross/head winds, no hilly terrain, etc.)...but I agree with you that 20+ mpg out of a 6.0L near 3-ton truck/SUV w/o some kind of "cheating" is practically impossible to obtain. It's not completely impossible to get 20 mpg out of a 6-liter (a lot of things would have to fall neatly into place in order for that to happen), but I would definitely call BS on someone claiming to get that out of a 6-liter even though driving at no less than 75 mph for a few hours straight (no coasting).