it isn't going to be a big diference. 18mpg sounds decent to me, i am lucky to see 16.

 

my wifes 07 Tahoe, netted a 18mpg on highway, that was driving 80-85 all the way to Dallas, and making 2 pit stops (my little boys needs to pee all the time ) of about 15-20mins each and with the truck staying on.... maybe it will do better driving at lower speeds, plus the tahoe only had about 500 miles, so Im pretty sure it wasnt broke in yet...

 

I asked over on the EFILive forum if the AFM controls would be accessible through EFILive. Seems it could be tweaked ever so slightly to work better.

 

That is what I like to hear. Tweaking is good.

 

Hell, I see 19.5-20 MPG in my 04 5.3 non-AFM truck every week. Of course I do about 90% highway miles, but am usually facing a strong headwind too.

 

In all the testing gm did on this system you will only use it abought 3% of the time not very much in my mind. But its a good selling ploy .

 

Yeah, I could definately see that being the case since it's so tough to keep it activated in normal driving.

When I test drove a AFM equipped AVY a while back there were plenty of times when I felt it could have been active when it wasn't. If the aftermarket tuning software gives people access to the control I bet it could be used much more than 3%.

 

My dad has an 07 Tahoe 5.3 with 4.10 gears. We drove it from Phx to Grand Junction this past summer and netted about 16 or 17 mpg. The only time I could get AFM to kick in is when I was on a downhill slope.

 

this afm almost sounds like dfco, where its mostly turned on during decel.

 

RGV seems to be right, only under extremly high vacuum conditions it's kickin in. It's probably dfco with a different name, instead of cutting all fuel, their squirtin four occasionaly. Yeah, Yeah, Thats the Ticket....