Ya i suppose to little extra rolling mass will bring it down some.

The 5.3 is not as fuel efficient as many who don't own them think they are. I babied the ceap out of mine in attempts to get goof fuel mileage and still never went above 17mpg on the highway

Depends on your setup. There's a tuned XFE on here with big wheels and 3.90s knocking down 22-24mpgs on the highway.

I'm gonna expose my ignorance here.....

What's a XFE?

My current company truck is a 2011 5.3 Z71 CCSB, my previous company truck was a 2009 5.3 Z71 ECSB. So far I am less than impressed with the 6 speed. It seems like the "tune" is very jerky/unrefined. I'm not sure how to explain that.

Anyway, my '11 averages about 1.5 mpg better than the '09. Considering they are almost identically equipped (both are 3.42 gears with the same tire/wheel package - the only real difference is ECSB vs CCSB), I'd say that's not bad. My '11 averages 16.3 mpg, and my '09 averaged just under 15 mpg. I would think with a tune the '11 could do A LOT better. The engine and tranny don't really seem to work together all the time...


My biggest gripe about the '11 is the ridiculous push set/push release parking brake. It makes setting the parking brake on the boat ramp a disaster with wet shoes/feet.

Basically it's a 2wd with better aerodynamics and some lighter weight aluminum parts (wheels and lower control arms, I think). Stands for eXtra Fuel Economy...


The 2011 is supposed to get 15 city/22 hwy/18 avg

I have the same truck. 14-15 city. 17 on the highway. 15.8 average on the computer. Truck has 13,000 miles.

Diablo Power Puck? Isn't that a handheld?

Power Puck is a handheld, unfortunately the 2011 Duramax trucks don't have much support in the custom tuning world. I was told HPTuners doesn't support them at all. I don't know about EFILive.