The 4-6-8 failed due to lack of computer power. The 4-6-8 shut the valves off by lifting the fulcrum of the rocker arm. The modern DOD uses oil pressure to collapse the lifters. Both intake and exhaust valves are turned off, so the cylinder becomes an air spring. Neither system cycles which cylinders are "off" either the set of4 is off while in 4 cylinder mode, or they are on. Doesn't alternate or anything like that and its the same 4 cylinders every time.
No announcement yet.
Should you make EFI super-lean at cruise?