AFM overactive

[JTDowdy]

2014 GMC Sierra 5.3.. AFM is switching back and forth between V8 and V4 more frequently or too much.  Check engine light has come on .  I havnt  gotten a chance to read the code yet, but the truck seems to be running normal until the AFM starts activating.  Put it in manual 5 and got it home without it switching back and forth.  Keep in mind I’m on a 6 inch lift and 35s. So my Truck doesn’t drop to V4 often anyways so this is abnormal.  But since the check engine light has come on my best example is at 45 with the cruise on, flat road and optimal conditions the truck will switch back and forth form v8 to v4 every 5 seconds .  Anybody experienced this ?  

[newdude]

Let us know what codes you find.  That will be your starting point.