I know this is going to be a giant gas bomb around a bunch of torch holding flamers but here we go:
My Tahoe:
2010 5.3 w/ DOD and 3.08 rear gear and RWD only.
LT3 w/ no NAV
Stock 17's on stock Rubber at 45 psi
Bone Stock Tahoe w/ 3rd row remove.
This is my DD in Savannah,GA (Read FLAT LAND W/ MINOR elevation chagnes +/- 50 ft.)
I have 2 stop lights and 2 stop signs each way to work ( M-F) and do most rural driving on the weekends. I follow the speeds limits which is predominately 45 and 55 mph. Yes I drive SLOW and use cruise control as much as possible, and accelerate like a grandma...what ever. I will consistently get 22.8-23.8 MPG Week in and Week Out... On the dash display for mpg and calculating from my gas receipts they both agree to .1 mpg, and I will consistantly get well over 600+ miles per tank...
Now driving on the high way i have noticed somethign very intersting.
@ 60-70 mph i will average 20-21 mpg. I wont get over 21.1 mpg. It doesn't matter 60 or 70 mpg, but I've noticed the DOD doesn't hardly go to V4 mode, and when it does it kicks back to V8 and drops mpg and then levels out.
@ 75 mph i will get 21-22 mpg. Very consistently 21. mpg. I've noticed it NEVER uses V4 mode and stays in V8 mode and is very light on the throttle.
I know it's a very particualr case on how I use the vehicle, but needless to say. Since I bought this vehicle, my drving style has changed. It's BIG, COMFY, ROOMY, QUIET(almost too quiet), Heavy, and I drive it accordingly. It gets me and whatever/who ever I can cram in it there in style and comfort. I'm thrilled and love it... And will definately be buying another one.