Finding ignition problems are one of a labscopes best assets, here are some examples.
86 Ford PU 7.5 V8 Ignition Primary signal.
Secondary Ignition, off single plug wire with secondary probe.
98 Ford Pickup Triton 5.4 V8 Coil on Plug (cop) Ignition.
78 Chev Monte Carlo, 5.7 V8 60k engine miles, my own personal driver. Secondary pattern, ever see one like this?
See a case study on this page