Last year, I replaced the 5.3 in my wife's 2007 Tahoe, due to problems with lifters on two separate cylinders (1 and 6). Engine had about 208,000 miles on it. Went back with a new GM engine.
About two months ago, replaced the AFM engine in my 2008 Silverado (212,000 miles) with a new Jasper engine. Same lifter problem as the Tahoe. Except Jasper makes a non-AFM engine, comes with a Diablo code reader, that allows you to re-program your computer, so it knows you ain't AFM anymore.
From my research, the AFM engines from 2007 thru 2014 were all the same design....a huge piece of crap, and I agree 100% with that......it's not IF you're gonna have problems, it's WHEN.
Starting in 2015, GM re-designed the AFM system, and they certainly needed to, and from I have seen and read, the new design has had no problems.
Both these vehicles used a little oil, and I never could figure out why. It wasn't burning it and there were no leaks. Come to find out that with those 4 cylinders not in use (1, 4, 6, and 7 I believe), the engine acted as a vacuum and oil was allowed to be sucked out and through those cylinders when there was no firing/compression on them. Very minutely of course, but still it was happening.
It is also my understanding that you cannot just turn off the AFM. I've seen modules you plug into the code port under the dash that supposedly turns it off, but you might research that.
I have been told you can go with the new 2015 designed AFM engine in the earlier vehicles, but I ain't sure about that. Computer would have to be re-programmed for that, but still possible I suppose.
You can google it and read hundreds of horror stories about the early AFM engine. But there a few out there that have never had a problem also.
I am extremely satisfied with my Jasper engine. Glad I went that route.
Last edited by kades51; Thu Mar 26 2020 08:40 PM.