LH6 GenIV aluminum 5.3 with AFM? That's what we have in the wife's Envoy. I bought it with brand spankin new GM bags with 63k on the clock. I sh*t an oil pressure sensor and when I replaced it, I discovered there's a little screen that goes under it. I managed to tear it and after that had occasional odd sensor readings. I think metal shavings find their way up there. I eventually replaced the screen and readings have been consistently. I know these motors have issues with the bypass piston sticking in the pump causing low pressure along with all the AFM BS. I keep an eye on it though, as long as you catch this stuff early the motors seem to survive.