My good friend had it on his Silverado. His engine developed a serious knock at about 90k miles and the dealer said he needed a new engine. Another good friend of mine is about the most intelligent mechanic/builder/tuner for GM you could ever find. He took the truck into his shop and said the issue is something failed in the DOD. DOD is displacement on demand. The same thing basically as AFM. He knew exactly what failed but I just know it failed. He said Chevy won't admit there is a problem with the system and they won't rebuild the engine to eliminate it. He did a DOD delete on it. It required quite a bit of engine work. New camshaft, lifters, and a bunch of other parts. As well as computer programming. The truck has been running great for a few years now. The owner still has it and lives 3 doors away from me. He's very glad that my guy managed to save his engine and eliminate DOD. He says the truck drives better and gets at least the same MPG as before the delete. My guy says any DOD or AFM system "sucks." He hates them and says they are problems. I just got this car and don't want it to have problems in several years from the crappy AFM system. I'm not terribly concerned with getting 1 mpg better mileage. There are AFM supporters that blame any failures of the system on bad maintenance. That may be true. But my neighbor had bought his Silverado new and claims he followed the severe service schedule for oil changes. And he doesn't operate the truck severely, almost never tows anything. Sometimes he tows a 2 place snowmobile trailer, that's it. I have not been able to find anyone that says disabling AFM causes problems. I really trust my engine guy that says it "sucks." I have this 2010 Equinox with the 2.4 engine that is committing suicide. From what I have read that 2.4 is terrible (it doesn't have AFM but the engine problems are so bad Chevy settled a class action lawsuit and rebuilt tons of engines, unfortunately mine is past the time limits for that repair). I'm selling this Equinox for a serious loss. So, I'm not real trusting of Chevrolet in all matters. I'm still a Chevy guy and bought this Blazer. But I want to disable the AFM before it screws up my engine.
