engine light came on and got this code after scanning p3400 cylinder deactivation code. seems like it is a problem when it goes from 8 to 4 cylinders for fuel savings?? i think. anyway wondering if anyone has had this issue and if it is going to cost me an arm and a leg to get fixed?? bought used 5 days ago. showed no signs of this trouble during test drive. naturally days later i'm having issues. got a warranty with it but they won't fix it until it is actually broken and if i just let it be until it becomes catastrophic failure i'm concerned it will cause other damages. any help would be appreciated. thanks.