The reason for this question is I recently finished a 5.3 drivetrain ( code LMG, flexfuel and active fuel management) intro my 1997 2dr 4wd Tahoe.
After all I am a bit disappointed 'cause this new drivetrain gets the same if not worse no. in the fuel consumption departement. With a very careful right foot I can get about 13,8mpg, nothing more is possible.
To get an impression what the original 5.3 drivetrain is capable of pls post your numbers.

Thx a lot

Harald

 

You do realize that you are posting a question about Tahoes in the Silverado section?
I moved one of them to the Tahoe section already.

 

I think it's a question about fuel consumption numbers of all trucks / SUV's with an 2007 5.3 drivetrain.

 

How long are you letting your average build up? or are you looking at the instant econ MPG? My 5.3 Tahoe gets about 14 MPG average econ, My 6.0 in the truck gets 12.5 average econ. I reset me average about once a month to see if I notice any differences. Looks like your getting normal mileage to me for the 5.3, but all in all its how you drive it.

 

Ok, I let the average build up a few weeks, maybe a month or a little longer.
My old 5.7 Vortec gave me better mileage and what is most annoying, I drove a 2000 Suburban in CA, NV including down to Death Valley and back and it averaged at about 15 - 16mpg and now with an actual, brand new drivetrain in a much lighter truck I have only 12 - 13mpg average.

All the new technology, active fuel management, seems to be worth nothing... hard to believe for me.
I hope the numbers will increase with a couple of thousand miles on my engine, it was brand new when I installed it..
Harald

 

Well I just learned in another thread that a new build will take up to 10,000 miles before the mileage gets better, sounds like a long breakin period but it does effect the mileage.