In my Corvette it's referred to as AFM (active fuel management") but it only switches from V4 to V8 mode, it never goes down to just two cylinders. A lot of people have had issues with bad lifters, as well as other driveline issues that can possibly be attributed to the vibrations caused when it switches back and forth between modes. Things such as the torque tube, transmission and torque convertor. For the first few years that I had my Corvette I let it go into V4 mode often and I ended up having to have the torque tube replaced under warranty. It's not clear if AFM caused it, or if it was just bad bearings that occurred due to heat (the heat from the exhaust is a known problem for the driveshaft bearings) But just to be safe I have been driving mostly in manual mode now (paddle shifting the automatic transmission keeps it out of V4 mode) I haven't had any hint of a problem with my lifters so far, fingers crossed I've got a good one here. I want to go well beyond 500,000 km on this engine someday. Hopefully the higher HTHS of M1 ESP 5w30 is of some help in this regard.