Originally Posted by johnmr12

Here is my experience. My 2015 silverado 5.3 with the "brilliantly" designed AFM system got a cylinder misfire code. It was cylinder 4. I had no idea what AFM even was at that point, so I did the typical troubleshooting steps. I swapped out the plug, then I swapped the coil pack with another cylinder, then I removed and cleaned the fuel injector. Nothing worked, so I pulled the valve cover and saw my intake valve was not functioning. Thats when I started researching the problem and learned all about AFM. I had noticed that the truck would burn about a quart of oil every few months, and I never could find a leak. So I took it to my mechanic, and he found that the cheap *** plastic lifter tray had spun the lifter. At that time he said the camshaft was ok, so he replaced the trays and lifters on the passenger side. I bought a device that plugs into your diagnostic port and disables the AFM. I ran for about 2 months and the exact same thing happened. My mechanic told me he was wrong about the camshaft being good, so it ate the new lifter. At that point he said since I needed a new camshaft he would have to do both heads. He is probably the most honest mechanic I have ever met so he agreed to only charge to do the drivers side and he would do the labor on the passenger side free. I decided at that point to get rid of AFM altogether so I bought an AFM delete kit, which came with everything to eliminate the AFM. But, you have to reprogram the control module so it doesn't know about the AFM. I found a guy in Missouri, sent him my module, and he programmed it for $50. My mechanic charged me about $1500, the delete kit was about $600. I had paid about $1500 for the first repair so if you do it right the first time, it should cost around $3,600. If it hasn't had any trouble yet, I recommend spending the $200 for the device that plugs into your diagnostic port. It prevents the AFM lifters from collapsing. By the way, since I removed the AFM crap, my truck no longer burns oil.

Originally Posted by countrysoldier

I recently had a delete done about 6-8 months ago. After getting the truck back, I was having an issue where my oil pressure would drop from ~40 lbs at cold crank to ~20 lbs at operation temps. Prior it would stay around the 40 range. Tried replacing the pressure sensor (took out the screen under it), found out the mechanic didn't put in the AFM plugs or the oil bypass plug so I did this myself. While doing this I put in a new oil pump and pick-up tube O-ring. After this the pressure still did the same. Thinking I got a bad sensor, I put another in. Still the same issue on oil pressure. Then about a month ago my new oil pump went out (I didn't prime it). So while putting another oil pump in, I pulled the crank and replaced the main bearings and rod bearings. Also put a new timing set in and replaced both front and rear main seals as well as another pressure sensor and put a new screen under it. Got all this done and the motor put back in the truck. Cranked it up (after priming the oil pump) and oil pressure cold was ~60 lbs. let the truck sit and idle about 30 mins while putting tires and some accessories back on. Once the truck got to operating temperature, my pressure had again dropped to ~20 lbs. I put 6 qts of oil in originally and got to thinking, the is what the manual says for oil change with filter, but I basically had a dry system with the engine apart and decided to double check the oil the next day. It was about a quart low, so I added another quart. Pressure at idle is still ~20 lbs after warming up. Am I missing something or is this normal? I have 184k miles on the odometer and bought the truck used with ~155k with no idea maintenance by previous owner(s).