Cordial greeting, I have an Optra Limited black lid, which leaves me intermittent the pulse of coil 1 and 4 as if it were welding with an electrode, the engine is difficult to turn on, in doing so they are failing cylinders due Coil, and Rich Crown so far I have not obtained a solution, another computer, CKP, CMP, coil ... Any opinion I will be grateful ... will also be proven ...