2010 Suburban 5.3L Here's the issue. I had a really weird unreproducable noise that had a metallic sound but would stop after a short period. Messing with gas, air, turning on offf, nothing can actively reproduce on que. Take the truck in, mechanic luckily hears it, they do work. Noise again, AC blower goes out back to the shop. I get her back yet again, noise again then stabilitrak needs service with a blinking check engine light, engine loss of power harsh shifting gears. Take her in, now they say I need a new motor, cyl 6 is misfiring. I just spent 2,500 now they want 6,500... I mean this is alot of money

 

More than likely AFM lifter failed and it needs lifters and a cam at the minimum.
AFM delete module and only synthetic oils in my '11, 122k miles and so far so good (knock on wood).

 

good morning. Thank you. I’m going to mention this to the dealership. They are recommending to get a new crate engine basically spend 6500.

 

My best guess is that a ton of metal shavings went through the motor and depending on mileage they are more comfortable with a fresh engine that can be warrantied and will give you problem free service.