I have never heard of the two firing thingy and don't want my brain to start seizuring while I try to figure it out. Interesting though, hopefully someone else can shed some light on this.
But it doesn't sound like it's firing twice, just that each plug fires differently from which electrode to which...ken4 said:What happens in waste spark ignition is that 1 coil pack fires 2 spark plugs simultaneously, e.g. cylinder 1 and cylinder 4. So while one spark plug is firing normally, spark jumps from center electrode to ground electrode, the other spark plug is firing in reverse, i.e. from ground electrode to center electrode,