Forgive my ignorance, A/M ignition

[Pete_89T2]

Originally Posted by NoDOHC

I thought that the stock coils fired using wasted spark. This is usually configured so that the current must pass through both plugs. It seems strange that a wasted spark system could possibly fire on only one of the plugs (are you sure about the cause of this symptom)? I am using the stock ignition and I only get misfires if I lean the mix up too much. Otherwise the engine purrs as smooth as glass. I think it might be more of an ECU issue.

The leadings coils fire wasted spark, the trailings do not. The leading coil is essentially one coil with its output wired in parallel with 2 towers. So for every spark event triggered on the input side of the leading coil, in theory you get a simultaneous spark firing at both leading plugs.