▁L 6 2 ▁" V 8 - 6 - 4 " ▁in ▁ 1 9 8 1 . ▁ ▁Second ▁generation ▁In ▁ 2 0 0 4 , ▁the ▁electron ics ▁side ▁was ▁improved ▁greatly ▁with ▁the ▁introdu ctions ▁of ▁Electron ic ▁Th rott le ▁Control , ▁electron ically ▁controlled ▁transm issions , ▁and ▁trans ient ▁engine ▁and ▁transmission ▁controls . ▁In ▁ ▁addition , ▁computing ▁power ▁was ▁vast ly ▁increased . ▁A ▁sol en oid ▁control ▁val ve ▁assembly ▁integrated ▁into ▁the ▁engine ▁valley ▁cover ▁contains ▁sol en oid ▁val ves ▁that ▁provide ▁a ▁press ur ized ▁oil ▁signal ▁to ▁spe cially ▁designed ▁hyd ra ul ic ▁roll er ▁lif ters ▁provided ▁by ▁E aton ▁Cor p . ▁and ▁Del phi . ▁These ▁lif ters ▁disable ▁and ▁re - enable ▁exhaust ▁and ▁int ake ▁val ve ▁operation ▁to ▁de activ ate ▁and ▁react iv ate ▁engine ▁cyl ind ers ▁. ▁Un like ▁the ▁first ▁generation ▁system , ▁only ▁half ▁of ▁the ▁cyl ind ers ▁can ▁be ▁de activ ated . ▁It ▁is ▁notable ▁that ▁the ▁second ▁generation ▁system ▁uses ▁engine ▁oil ▁to ▁hyd ra ul ically ▁mod ulate ▁engine ▁val ve ▁function . ▁As ▁a ▁result , ▁the ▁system ▁is ▁dependent ▁upon ▁the ▁quality ▁of ▁the ▁oil ▁in ▁the ▁engine . ▁As ▁anti - fo aming ▁agents ▁in ▁engine ▁oil ▁are ▁de ple ted , ▁air ▁may ▁become ▁entra ined ▁or ▁dissol ve ▁in ▁the ▁oil , ▁delay ing ▁the ▁timing ▁of ▁hyd ra ul ic ▁control ▁signals . ▁Similarly ▁engine ▁oil