2014 GMC Sierra 1500 5.3L MPG Tune

[DrDan]

I can actually feel the AFM working, plus it makes my pipes sound crappy when it goes to 4 cyl., I'm going to leave it off.
Another good reason to leave it off is by the way the 4 cylinder mode is achieved, by taking away oil pressure to the valve train. That just can't be good? I did a little driving today, mostly in town, and I do like the 87 octane tune. Did a nice burn out and didn't even mean to.
My shift points are pretty consistant 1-2 @ 10mph, 2-3 @ 20, 3-4 @ 30, & 4-5 @ 40 just normal driving. Pulled on to the highway this morning and the shifting was around the 4000 rpm mark. ( didn't have it all the way down ) Pretty good, I was running 70 in a very short period of time. If I get decent fuel mileage I'll be happy.
As far as warranty goes, I'm not worried, because I can always set it back to stock. Can they really blame an engine failure on the AFM being on?
I really can't see any harm in disabling AFM...you just have a V8 all the time. Oil flows as it should.
I think your right foot has more to do with fuel mileage than AFM.