you guys do realize you can reset the average MPG readout right?, same button that resets trip, timer, ect.
after 10k miles its calculating the average of all 10k miles and doesnt change at all. If you reset every couple seconds you can see your instant MPG's.
my truck tends to get stuck at 16.9 avg after about 5k miles., even running the **** out of it towing the race car 3 hours away and back wont change it.

 

i'm averaging 18.1mpg. i have a K&N air filter and a CGS catback exhaust system

 

09 z85/71 3500 miles. In oct. with 500 miles I was getting a hair over 14. (manual calculations) I'm over 3500 miles and just past 15 mpg this week. I maybe wrong... but doesn't the mileage improve as it (sort of) breaks in?

 

I reset my, trip,fuel used,avg mpg at every fill up, I just filled up 30min at of this writing with a 5.3L I got 17.1mpg.

Thats with back and forth to work, a trip out to the lake, picking up the kids at practice.

Its HOW you drive, keep a space between me and the car in front in traffic so i can coast as much as possible, coast at off ramps, roll up to stop lights and sop signs.
If you are having to get on the brakes to come to a stop then you are more then likely accelerating too much only to have to pull it all back down for the stop.
As much as possible use your brakes to stop the vehicle not constantly slow it...

I've been tracking my mileage ever since I bought my truck new in Oct 07 and have never gotten less then 15.3MPG

73shark pointed this out a while back and I can say that yes its true because I do it, is to use the tow/haul mode in city traffic or stop and go traffic it will add a tad more mpg per mile.

 

oh and that is zero mods, syntheic oil, factory tires @32psi air and yes from time to time I do get on it and have been know to race...