Welcome. Looks like you found a nice Silverado.
Many of us on here have a Diablosport Intune for turning off the AFM. But it also allows you to get a custom tune which gives a little boost in power and a huge boost in trans shifting characteristics.
You can read about many experiences on here:
Search results for query: lew tune
He has a website where you can buy the tuner and get started with the email tuning process:
DiabLew Tune - Custom Tuning for GM Vehicles - DiabloSport inTune 2030, Diablo inTune 8245 Platinum, DiabloSport Trinity, inTune, DiabloSport Trinity 9245 Platinum, Custom Tuning by 06MonteSS, custom GM tuning
I chose to purchase a used intune from another member at a much lower price and then reached out to Lew for the custom tune.
Not sure if this one is still available:
Diablo Intune I3 Platinum Tuner
Your truck can use the oldest i1000, or the later i2030 (which is what I have) or the newer i3.
If you dont want the custom tune, you can use a canned tune or just turn off AFM with no tune. The canned tunes are nothing like what the custom tune can do.
But lastly, if you dont want a tuner, there are plug in devices that deactivate AFM. You just plug them into the OBD2 port and leave them in there.
Buy New Range Technology AFM-DFM DISABLER,Blue,Compatible with V6 & V8 GM Motors: Engine Management Systems - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
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For the price of these (they can be bought used also) I would go for an intune personally.