I wanted to post something positive about these 5.3 ltr, AFM engines. I have a 2009 Silverado with a 5.3 ltr oil consuming engine. Since I have owned it, it had used a quart every 1,000 miles if I have been on the interstate. I have always hated the AFM, because, when activated, the truck seems to vibrate, so I just shift in to manual and 5th gear. That way it would not use AFM at all. The only solution for the AFM was to purchase a $400 programmer and delete it.
I recently had an engine light come on. As it turned out, it was my oil pressure sending unit... couple of hundred bucks to fix. The engine always would let me know when it had been parked on a hill, low on oil, in need of an oil change, etc. So, I decided not to replace the sensor.
Something wonderful happened, I noticed that the AFM DID NOT WORK without a oil pressure sending unit. The truck is much more enjoyable to drive. It does not vibrate, gas milage change is less than noticeable, AND IT QUIT USING AS MUCH OIL ! The filter doesn't stop up and I could be more pleased.
After using Synthetic Oil for a while, without any improvements in the sludge department, I found out NAPA had a Gold Filter for Synthetic Oil ! It just keeps getting better. First oil change in 3 years the truck went 7,500 miles before needing a pre-mature oil change and the TICK seems to be a thing of the past as well.