[winks79]

The only one I've owned that I did not disable AFM, gave me problems, 08' Z71 Avalanche. At 90k went in to dealer for loud tick that just showed up out of nowhere. Warranty covered it, but they had to replace, cam, lifters, oil pump, etc. Was told by the mechanic that it was AFM that caused issue, and suggested that I disable it. Said they had fixed many with the same issues, that I was lucky that mine was still under warranty. From then on, no AFM for me on any more of my trucks. Not going to take the chance, and have not had any more issues.

 

[winks79]

The Avalanche I spoke of in the earlier post I bought new. Changed my own oil in it. Was overkill, but changed it every 3k miles with 5W30 Pennzoil and always used AC filters. it never used any oil at all. Put 90k miles on it before any issue. Just went out to start one day and started tapping lightly while idling. Started to drive it, and tapping got very loud around 2k rpm, could hear it pretty good inside truck. My mechanic at the dealership I use is very knowledgeable and stated that he had replaced the camshaft and lifters on many of these 5.3's and suggested I delete the AFM, that it was a known problem, and GM would not do anything about it. He stated that the engine looked brand new as far as cleanliness, said did not look like it had 90k on it. I told him how often I changed the oil, and he laughed and said that it showed. I have since owned 3 other AFM vehicles and have deleted the AFM on them all and not had another issue. Just not willing to gamble, and it really does not affect my mileage at all. I personally hate it. On my current truck I have a Diablew tune, and my mileage has increased by 2 mpg since having Lew to tune it. Don't need the stinking AFM for mileage anyway, mine is proof.