You don't say what kind of ignition system this four banger has but in any case, you will be able to see all the ignition events with your 4423. I suspect you simply do not have enough capture time on the screen to see all the events. Put enough time to see one or more engine cycles and adjust the sample rate to achieve 1us sample intervals in properties.
If it is a distributor ignition, then only two channels are needed. One will be on the coil wire and the other on a plug wire just for sync. Chose the inverted probe for this system.
If it is a waste spark system (two coils no distributor), then you would place a channel on each plug wire. Two of these will be positively fired and two negative. Choose the inverted probe for the negative ones and the positive probe for the positive cylinders.
Hope this is helpful.
(The Picotologist) http://www.autonerdz.com
THE PicoScope Automotive Authority
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