5.3 from hell....... I had an AFM lifter crap out on my 09, 52 thousand miles, took it to the gmc garage, $2700 and a week later, it runs, but the oil pressure drops so low it locks a code. Also, the AFM, which is what they were supposed to fix, doesn't work. I removed and replaced the lifter oil filter and sender (which you can do without any special tools or removing anything else - lots of youtube videos of it) but no help. I think they contaminated the sump and crap went through the oil pump. I cut the filter open (600 miles on it) and it was full of metal. The oil looked like sick metal flake paint. Back to the garage, where they wanted another $1800 to fix it. I told them to keep the piece of crap. Then they said they would replace the pump, put in a new suction o-ring, install the baffle later 5.3s have for $750, so I told 'em to do it. They pulled the cam, and it had spun a bearing. They also replaced all that for the same price. This time it took 2 weeks and 2 days....... It does run well now, and has great oil pressure, but I feel like I can't trust it now, and feel like GM pulled another "let's develop this technology on the road at our customer's expense" trick. I could have had a new motor in less time and probably less $$. So don't ignore your low oil pressure warning.... and don't but any 2007-8-9 AFM equipped pos.