IS AFM DISABLEMENT NECESSARY??

[MrMonte]

I turned off the AFM via a tune on my 2018 Yukon Denali, use Mobil 1 oil & OEM filter every 5-6K miles. I still had an AFM lifter fail at 82K miles then did a cam/lifter upgrade deleting the AFM system. Now at 115K miles and enjoying the extra power & better mileage. I did a 2k mile road trip last month and averaged 21.2mpg with avg speed of 79mph. I'm running 305 summer tires that are 33" tall which did hurt my mileage some. My speedometer has been adjusted to match a GPS.

My son had an AFM lifter fail at 115K on his 2015 Yukon Denali.

 

[tooleyondeck]

It's the eternal-debate on this platform, but I would say if you're the type to only keep a vehicle for a few years then trade it in, then nah don't bother, just get a Range. If this is a keeper and you want it to be dependable for years, then a mechanical delete and retune is the only way to guarantee you won't have problems.

 

[Marky Dissod]

... AFM is a problem it will cost a bunch of money to fix it, starting with new heads and some computer programing.

I'm beyond convinced GM came up with V4 mode because their V8s were TOO long-lived -
they want everyone needing another vehicle after 150,000-175,000 miles.
Engines that last 250,000 miles on average are bad for GM 's bottom line.

... never heard a peep from AFM. It is the luck of the draw.

How'd your transmission do?

... always ran 87 octane in my 2011. In the year I sold it I started putting premium in it on road trips. It made a significant difference difference in power.

The real benefit of 91 / 93 octane, believe it or not, is NOT the extra power, it's not even the MpG improvement -
it's the additional lubricants and cleaners that limit carbon buildup and reduce cylinder wall wear.